CN110601565B - Linear power supply with retrace type overcurrent protection function - Google Patents

Abstract

The invention discloses a linear power supply with a foldback overcurrent protection function, comprising an AC power input terminal, a voltage stabilizing filter unit, a high-power linear control module and a DC power output terminal, and is characterized in that: the AC power input terminal is electrically connected to the voltage stabilizing filter unit; the voltage stabilizing filter unit is electrically connected to the high-power linear control module, and the high-power linear control module is electrically connected to the DC power output terminal; the AC power input terminal is used to perform safety protection and temperature control protection on the AC power supply; the voltage stabilizing filter unit is used to perform power frequency voltage reduction on the input AC power supply, and perform rectification filtering and power stabilization, and supply power to the high-power linear control module; the high-power linear control module is used to sample, filter and compare the current output by the voltage stabilizing filter unit, and control the voltage stabilizing filter unit according to the comparison signal, and at the same time sample the output voltage and fine-tune the output voltage.

Description

A linear power supply with foldback overcurrent protection function

Technical Field

The invention relates to the field of linear power supply equipment, in particular to a linear power supply with a foldback overcurrent protection function.

Background Art

Compared with switching power supplies, linear power supplies can meet the power needs of devices that are sensitive to power noise due to their stable performance, no interference such as high-frequency ripple, and small size. However, the biggest disadvantage of linear power supplies is that they generate a lot of heat and have low energy utilization.

For power devices, when the load current is large or working in a short-circuit state, it will affect the normal operation of the circuit and even damage the power tube. Therefore, in order to avoid damage to the power device when the load current exceeds the normal working range, an overcurrent protection module should be integrated inside the power management chip to limit the maximum operating current of the power tube.

Summary of the invention

The technical problem to be solved by the present invention is to provide a linear power supply with a foldback overcurrent protection function. The linear power supply can adjust the working state of the linear power supply by sampling and analyzing the output voltage, thereby adjusting the output voltage, avoiding failure of the linear power supply and downstream equipment due to short circuit or overcurrent, and improving the reliability of the linear power supply.

The present invention adopts the following technical solutions to achieve the invention objectives:

A linear power supply with a foldback overcurrent protection function, comprising an AC power input terminal, a voltage stabilizing filter unit, a high-power linear control module and a DC power output terminal, and is characterized by:

The AC power input terminal is electrically connected to the voltage stabilizing and filtering unit;

The voltage stabilizing and filtering unit is electrically connected to the high-power linear control module and the DC power supply output terminal, and the high-power linear control module is electrically connected to the DC power supply output terminal;

The AC power input terminal is used to provide safety protection for the AC power supply;

The voltage stabilizing and filtering unit is used to reduce the input AC power supply voltage at the industrial frequency, perform rectification and filtering, and power stabilization, and supply power to the high-power linear control module;

The high-power linear control module is used to sample, filter and compare the current output by the voltage stabilizing and filtering unit, and control the voltage stabilizing and filtering unit according to the comparison signal, and fine-tune the output voltage at the same time;

The DC power supply output terminal is used to perform polarity protection and overvoltage protection on the DC power supply.

As a further limitation of the present technical solution, the AC power input end includes an L end, an N end and an E end, the L end is electrically connected to one end of the capacitor C1 and the common-mode inductor L1, the N end is electrically connected to the other end of the capacitor C1 and the common-mode inductor L1, the common-mode inductor L1 is electrically connected to both ends of the capacitor C2 and one end of the capacitor C3, the common-mode inductor L1 is electrically connected to one end of the switch S1, the anode of the thyristor SR1 and one end of the resistor R1, the other end of the resistor R1 is electrically connected to one end of the capacitor C4, the other end of the switch S1 is electrically connected to one end of the resistor R2, the other end of the resistor R2 is electrically connected to the gate of the thyristor SR1 and one end of the resistor R3, the cathode of the thyristor SR1 is electrically connected to one end of the resistor R3, the E end is grounded, and the other end of the capacitor C3 is grounded.

As a further limitation of the present technical solution, the voltage stabilizing and filtering unit includes a transformer T1, the other end of the resistor R3, the other end of the capacitor C4 and the negative electrode of the thyristor SR1 are electrically connected to the input end of the transformer T1 respectively, one output end of the transformer T1 is electrically connected to the rectifier bridge D1, the other output end of the transformer T1 is electrically connected to the rectifier bridge D3, the rectifier bridge D1 is electrically connected to one end of the capacitor C5, the collector of the transistor Q1, the collector of the transistor Q2 and the collector of the transistor Q3, the emitter of the transistor Q1 is electrically connected to the base of the transistor Q2 and the base of the transistor Q3, the emitter of the transistor Q2 is electrically connected to the resistor R4, the emitter of the transistor Q3 is electrically connected to the resistor R5, and the rectifier bridge D3 is electrically connected to one end of the capacitor C10 and the voltage stabilizing chip U1.

As a further limitation of the present technical solution, the other end of the capacitor C10 and the voltage stabilizing chip U1 are respectively electrically connected to the GND end of the high-power linear control module M1, the voltage stabilizing chip U1 is electrically connected to the VCC end of the high-power linear module M1, the B end of the high-power linear module M1 is electrically connected to the base of the transistor Q1, the CS+ end and the CS- end of the high-power linear control module M1 are respectively electrically connected to one end of the resistor R6, the W1 end and the W2 end of the high-power linear control module M1 are connected to the variable resistor R41, the +S end of the high-power linear control module M1 is grounded, and the -S end of the high-power linear control module M1 is connected to the VOUT- end.

As a further limitation of the present technical solution, the high-power linear control module M1 includes a resistor R22 and a resistor R23, one end of the resistor R22 is electrically connected to one end of the capacitor C94, one end of the capacitor C84, one end of the resistor R21, and the reverse input end of the operational amplifier U2A, one end of the resistor R23 is electrically connected to the other end of the capacitor C94, one end of the resistor R24, and the positive input end of the operational amplifier U2A, the other end of the resistor R24 is grounded, the other end of the capacitor C84, the other end of the resistor R21, and the output end of the operational amplifier U2A are respectively electrically connected to one end of the resistor R20, the other end of the resistor R20 is electrically connected to the positive input end of the operational amplifier U2B, one end of the resistor R42 is connected to the capacitor C14, and the other end of the resistor R42 is electrically connected to the resistor R11, the resistor R12, the negative electrode of the diode D24, the capacitor C24, the capacitor C34, and one end of the resistor R16. The positive electrode of the capacitor C14, the diode D24 and the other end of the capacitor C24 are grounded respectively, the other end of the resistor R11 and the other end of the resistor R12 are electrically connected to one end of the resistor R13 respectively, the other end of the resistor R13 is electrically connected to one end of the resistor R14, the other end of the resistor R14 is electrically connected to one end of the resistor R15, the other end of the resistor R15 is grounded, the other end of the resistor R11 and the other end of the resistor R12 are electrically connected to the reverse input end of the operational amplifier U2B respectively, the output end of the operational amplifier U2B is electrically connected to one end of the capacitor C74 and one end of the resistor R19, the other end of the capacitor C74 is electrically connected to the reverse input end of the operational amplifier U2B, the other end of the resistor R19 is electrically connected to the base of the transistor Q34, the emitter of the transistor Q34 is grounded, and the collector of the transistor Q34 is connected to the B end of the high-power linear control module M1.

As a further limitation of the present technical solution, the high-power linear control module M1 also includes a resistor R9, a resistor R10, a resistor R47 and a resistor R48, the other end of the resistor R9 and the other end of the resistor R10 are respectively electrically connected to the -S end of the high-power linear module M1, one end of the resistor R47 is electrically connected to one end of the resistor R9, one end of the resistor R48 is electrically connected to one end of the resistor R10, the other end of the resistor R47 is electrically connected to the other end of the resistor R9, the other end of the resistor R48 is electrically connected to the other end of the resistor R10, and the other end of the resistor R42 is electrically connected to the other end of the resistor R10. One end of the resistor R43 is electrically connected to one end of the resistor R43 and one end of the resistor R44, one end of the resistor R43 is electrically connected to one end of the resistor R45, the other end of the resistor R44 is electrically connected to one end of the resistor R46, the other end of the resistor R46 is electrically connected to the other end of the resistor R45, the other end of the resistor R45 is electrically connected to the other end of the resistor R47, the other end of the resistor R45, the other end of the resistor R46, the other end of the resistor R47 and the other end of the resistor R8 are electrically connected to the capacitor C64 respectively. One end of the capacitor C64 is electrically connected to the W2 end of the high-power linear control module M1, and the other end of the capacitor C64 is electrically connected to the W2 end of the high-power linear control module M1. One end of the capacitor C64, the other end of the resistor R45, the other end of the resistor R46, the other end of the resistor R47 and the other end of the resistor R48 are electrically connected to the cathode of the diode D14, and the anode of the diode D14 is electrically connected to the +S end of the high-power linear module M1. The +S end of the high-power linear module M1 is grounded. The other end of the resistor R45, the other end of the resistor R46, the other end of the resistor R47 and the other end of the resistor R48 are electrically connected to the cathode of the diode D14, and the anode of the diode D14 is electrically connected to the +S end of the high-power linear module M1. The +S end of the high-power linear module M1 is grounded. The other end of the capacitor C54 is electrically connected to the -V end of the high-power linear module M1, the other end of the resistor R43, the other end of the resistor R44, one end of the resistor R45 and one end of the resistor R46 are electrically connected to the positive input end of the operational amplifier U1A, the other end of the capacitor C34 and the other end of the resistor R16 are electrically connected to one end of the resistor R17, the other end of the resistor R17 is grounded, the other end of the capacitor C34 and the other end of the resistor R16 are electrically connected to the reverse input end of the operational amplifier U1A, The operational amplifier U1A is electrically connected to one end of the capacitor C44, the other end of the capacitor C44 is grounded, the output end of the operational amplifier U1A is electrically connected to one end of the resistor R18, the other end of the resistor R18 is electrically connected to the collector of the transistor Q34 and the B end of the high-power linear module M1, the other end of the resistor R43, the other end of the resistor R44, one end of the resistor R45 and one end of the resistor R46 are electrically connected to the positive input end of the operational amplifier U1B, the reverse input end of the operational amplifier U1B and the reverse input end of the operational amplifier U1B The output end is connected, the output end of the operational amplifier U1B is electrically connected to one end of the resistor R25, the other end of the resistor R25 is electrically connected to the positive input end of the operational amplifier U3A and the positive input end of the operational amplifier U3B, the other end of the resistor R42 is electrically connected to one end of the resistor R26, the other end of the resistor R26 is electrically connected to one end of the resistor R27, the other end of the resistor R27 is electrically connected to one end of the resistor R28, one end of the capacitor C11, one end of the capacitor C10, and the reverse input end of the operational amplifier U3A, the other end of the capacitor C11 is electrically connected to the positive input end of the operational amplifier U3A. The VCC end of the high-power linear module M1, one end of the capacitor C11 is electrically connected to one end of the resistor R28, one end of the capacitor C10 and the reverse input end of the operational amplifier U3A, one end of the resistor R28 is electrically connected to one end of the capacitor C10 and the reverse input end of the operational amplifier U3A, one end of the capacitor C10 is electrically connected to the reverse input end of the operational amplifier U3A, the reverse input end of the operational amplifier U3B is electrically connected to the other end of the resistor R28, the other end of the capacitor C10 and one end of the resistor R29, and the other end of the resistor R29 is electrically connected to the reverse input end of the operational amplifier U3A. The output end of the operational amplifier U3A is electrically connected to one end of the resistor R31, the other end of the resistor R31 is electrically connected to the base of the transistor Q14, the collector of the transistor Q14 is electrically connected to the other end of the resistor R13 and one end of the resistor R14, the emitter of the transistor Q14 is grounded, the output end of the operational amplifier U3B is electrically connected to one end of the resistor R30, the other end of the resistor R30 is electrically connected to the base of the transistor Q24, the collector of the transistor Q24 is electrically connected to the other end of the resistor R14 and one end of the resistor R15, and the emitter of the transistor Q24 is grounded.

As a further limitation of the present technical solution, the DC power supply output end includes a VOUT+ end and a Vout- end, the rectifier bridge D1, the capacitor C5, and the -V end of the high-power linear module M1 are electrically connected to the Vout- end respectively, the other end of the resistor R6 is electrically connected to the VOUT+ end, the VOUT+ end is electrically connected to the overvoltage protection chip M2, one end of the capacitor C6, one end of the capacitor C7, one end of the capacitor C8, one end of the capacitor C9 and the negative electrode of the diode D2, and the VOUT- end is electrically connected to the overvoltage protection chip M2, the other end of the capacitor C6, the other end of the capacitor C7, the other end of the capacitor C8, the other end of the capacitor C9 and the positive electrode of the diode D2.

Compared with the prior art, the advantages and positive effects of the present invention are:

The present invention is a linear power supply with a foldback overcurrent protection function. The output voltage is sampled and detected by a hardware circuit with special functions in the linear power supply, and overcurrent protection is realized in combination with a high-power linear control module and a voltage stabilizing filter unit. The power conversion, on/off control, overcurrent protection and short-circuit protection functions of the linear power supply can be realized. The linear power supply has multiple protection functions, and can effectively protect the linear power supply under different use conditions, thereby improving the safety of the power supply.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a block diagram of the principle of the present invention.

FIG. 2 is a schematic diagram of the main circuit design of the present invention.

FIG. 3 is a schematic diagram of a high-power linear control module of the present invention.

DETAILED DESCRIPTION

A specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation.

As shown in Figures 1-3, the present invention includes an AC power input terminal, a voltage stabilizing filter unit, a high-power linear control module and a DC power output terminal.

The AC power input terminal is electrically connected to the voltage stabilizing and filtering unit;

The voltage stabilizing and filtering unit is electrically connected to the high-power linear control module and the DC power supply output terminal, and the high-power linear control module is electrically connected to the DC power supply output terminal;

The AC power input terminal is used to provide safety protection for the AC power supply;

The voltage stabilizing and filtering unit is used to reduce the input AC power supply voltage at the industrial frequency, perform rectification and filtering, and power stabilization, and supply power to the high-power linear control module;

The high-power linear control module is used to sample, filter and compare the current output by the voltage stabilizing and filtering unit, and control the voltage stabilizing and filtering unit according to the comparison signal, and fine-tune the output voltage at the same time;

The DC power supply output terminal is used to perform polarity protection and overvoltage protection on the DC power supply.

The AC power input end includes an L end, an N end and an E end, the L end is electrically connected to one end of the capacitor C1 and the common-mode inductor L1, the N end is electrically connected to the other end of the capacitor C1 and the common-mode inductor L1, the common-mode inductor L1 is electrically connected to both ends of the capacitor C2 and one end of the capacitor C3, the common-mode inductor L1 is electrically connected to one end of the switch S1, the anode of the thyristor SR1 and one end of the resistor R1, the other end of the resistor R1 is electrically connected to one end of the capacitor C4, the other end of the switch S1 is electrically connected to one end of the resistor R2, the other end of the resistor R2 is electrically connected to the gate of the thyristor SR1 and one end of the resistor R3, the cathode of the thyristor SR1 is electrically connected to one end of the resistor R3, the E end is grounded, and the other end of the capacitor C3 is grounded.

The voltage stabilizing and filtering unit includes a transformer T1, the other end of the resistor R3, the other end of the capacitor C4 and the negative electrode of the thyristor SR1 are electrically connected to the input end of the transformer T1 respectively, one output end of the transformer T1 is electrically connected to the rectifier bridge D1, the other output end of the transformer T1 is electrically connected to the rectifier bridge D3, the rectifier bridge D1 is electrically connected to one end of the capacitor C5, the collector of the transistor Q1, the collector of the transistor Q2 and the collector of the transistor Q3, the emitter of the transistor Q1 is electrically connected to the base of the transistor Q2 and the base of the transistor Q3, the emitter of the transistor Q2 is electrically connected to the resistor R4, the emitter of the transistor Q3 is electrically connected to the resistor R5, and the rectifier bridge D3 is electrically connected to one end of the capacitor C10 and the voltage stabilizing chip U1.

The other end of the capacitor C10 and the voltage stabilizing chip U1 are respectively electrically connected to the GND end of the high-power linear control module M1, the voltage stabilizing chip U1 is electrically connected to the VCC end of the high-power linear module M1, the B end of the high-power linear module M1 is electrically connected to the base of the transistor Q1, the CS+ end and the CS- end of the high-power linear control module M1 are respectively electrically connected to one end of the resistor R6, the W1 end and the W2 end of the high-power linear control module M1 are connected to the variable resistor R41, the +S end of the high-power linear control module M1 is grounded, and the -S end of the high-power linear control module M1 is connected to the VOUT- end.

The high-power linear control module M1 includes a resistor R22 and a resistor R23, one end of the resistor R22 is electrically connected to one end of the capacitor C94, one end of the capacitor C84, one end of the resistor R21, and the reverse input end of the operational amplifier U2A, one end of the resistor R23 is electrically connected to the other end of the capacitor C94, one end of the resistor R24, and the positive input end of the operational amplifier U2A, the other end of the resistor R24 is grounded, the other end of the capacitor C84, the other end of the resistor R21, and the output end of the operational amplifier U2A are electrically connected to one end of the resistor R20, respectively, the other end of the resistor R20 is electrically connected to the positive input end of the operational amplifier U2B, one end of the resistor R42 is connected to the capacitor C14, the other end of the resistor R42 is electrically connected to the resistor R11, the resistor R12, the cathode of the diode D24, the capacitor C24, the capacitor C34, and one end of the resistor R16, the capacitor C 14. The anode of the diode D24 and the other end of the capacitor C24 are grounded respectively, the other end of the resistor R11 and the other end of the resistor R12 are electrically connected to one end of the resistor R13 respectively, the other end of the resistor R13 is electrically connected to one end of the resistor R14, the other end of the resistor R14 is electrically connected to one end of the resistor R15, the other end of the resistor R15 is grounded, the other end of the resistor R11 and the other end of the resistor R12 are electrically connected to the reverse input end of the operational amplifier U2B respectively, the output end of the operational amplifier U2B is electrically connected to one end of the capacitor C74 and one end of the resistor R19, the other end of the capacitor C74 is electrically connected to the reverse input end of the operational amplifier U2B, the other end of the resistor R19 is electrically connected to the base of the transistor Q34, the emitter of the transistor Q34 is grounded, and the collector of the transistor Q34 is connected to the B end of the high-power linear control module M1.

The high-power linear control module M1 also includes a resistor R9, a resistor R10, a resistor R47 and a resistor R48. The other end of the resistor R9 and the other end of the resistor R10 are respectively electrically connected to the -S end of the high-power linear module M1. One end of the resistor R47 is electrically connected to one end of the resistor R9. One end of the resistor R48 is electrically connected to one end of the resistor R10. The other end of the resistor R47 is electrically connected to the other end of the resistor R9. The other end of the resistor R48 is electrically connected to the other end of the resistor R10. The other end of the resistor R42 is electrically connected to one end of the resistor R43. The other end of the resistor R43 is electrically connected to one end of the resistor R44, the other end of the resistor R43 is electrically connected to one end of the resistor R45, the other end of the resistor R44 is electrically connected to one end of the resistor R46, the other end of the resistor R46 is electrically connected to the other end of the resistor R45, the other end of the resistor R45 is electrically connected to the other end of the resistor R47, the other end of the resistor R45, the other end of the resistor R46, the other end of the resistor R47 and the other end of the resistor R8 are electrically connected to one end of the capacitor C64 respectively, and the capacitor C64 The other end is electrically connected to the W2 end of the high-power linear control module M1, one end of the capacitor C64, the other end of the resistor R45, the other end of the resistor R46, the other end of the resistor R47 and the other end of the resistor R48 are electrically connected to the cathode of the diode D14, the anode of the diode D14 is electrically connected to the +S end of the high-power linear module M1, the +S end of the high-power linear module M1 is grounded, the other end of the resistor R45, the other end of the resistor R46, the other end of the resistor R47 and the other end of the resistor R48 are electrically connected to the capacitor C5 4, the other end of the capacitor C54 is electrically connected to the -V end of the high-power linear module M1, the other end of the resistor R43, the other end of the resistor R44, one end of the resistor R45 and one end of the resistor R46 are electrically connected to the positive input end of the operational amplifier U1A respectively, the other end of the capacitor C34 and the other end of the resistor R16 are electrically connected to one end of the resistor R17 respectively, the other end of the resistor R17 is grounded, the other end of the capacitor C34 and the other end of the resistor R16 are electrically connected to the negative input end of the operational amplifier U1A respectively, the operational amplifier U1A The amplifier U1A is electrically connected to one end of the capacitor C44, the other end of the capacitor C44 is grounded, the output end of the operational amplifier U1A is electrically connected to one end of the resistor R18, the other end of the resistor R18 is electrically connected to the collector of the transistor Q34 and the B end of the high-power linear module M1, the other end of the resistor R43, the other end of the resistor R44, one end of the resistor R45 and one end of the resistor R46 are electrically connected to the positive input end of the operational amplifier U1B, the reverse input end of the operational amplifier U1B is connected to the output end of the operational amplifier U1B, The output end of the operational amplifier U1B is electrically connected to one end of a resistor R25, the other end of the resistor R25 is electrically connected to the positive input end of the operational amplifier U3A and the positive input end of the operational amplifier U3B, the other end of the resistor R42 is electrically connected to one end of a resistor R26, the other end of the resistor R26 is electrically connected to one end of a resistor R27, the other end of the resistor R27 is electrically connected to one end of a resistor R28, one end of a capacitor C11, one end of a capacitor C10, and the reverse input end of the operational amplifier U3A, the other end of the capacitor C11 is electrically connected to the high power The VCC end of the linear module M1, one end of the capacitor C11 is electrically connected to one end of the resistor R28, one end of the capacitor C10 and the reverse input end of the operational amplifier U3A, one end of the resistor R28 is electrically connected to one end of the capacitor C10 and the reverse input end of the operational amplifier U3A, one end of the capacitor C10 is electrically connected to the reverse input end of the operational amplifier U3A, the reverse input end of the operational amplifier U3B is electrically connected to the other end of the resistor R28, the other end of the capacitor C10 and one end of the resistor R29, and the other end of the resistor R29 is grounded. The output end of the operational amplifier U3A is electrically connected to one end of the resistor R31, the other end of the resistor R31 is electrically connected to the base of the transistor Q14, the collector of the transistor Q14 is electrically connected to the other end of the resistor R13 and one end of the resistor R14, the emitter of the transistor Q14 is grounded, the output end of the operational amplifier U3B is electrically connected to one end of the resistor R30, the other end of the resistor R30 is electrically connected to the base of the transistor Q24, the collector of the transistor Q24 is electrically connected to the other end of the resistor R14 and one end of the resistor R15, and the emitter of the transistor Q24 is grounded.

The DC power supply output end includes a VOUT+ end and a Vout- end. The rectifier bridge D1, the capacitor C5, and the -V end of the high-power linear module M1 are electrically connected to the Vout- end respectively. The other end of the resistor R6 is electrically connected to the VOUT+ end. The VOUT+ end is electrically connected to the overvoltage protection chip M2, one end of the capacitor C6, one end of the capacitor C7, one end of the capacitor C8, one end of the capacitor C9, and the negative electrode of the diode D2. The VOUT- end is electrically connected to the overvoltage protection chip M2, the other end of the capacitor C6, the other end of the capacitor C7, the other end of the capacitor C8, the other end of the capacitor C9, and the positive electrode of the diode D2.

The AC power input terminal is used to perform safety protection and temperature control protection on the AC power.

The transistor Q2 and the transistor Q3 are redundant with each other.

The linear power supply startup working process in the present invention is as follows:

As shown in Figure 2, after the L and N terminals of the AC power input of the linear power supply are powered, they pass through the protection circuit part and then are stepped down by the transformer T1. Another part of the stepped-down current passes through the voltage regulator chip U1 to supply power to the high-power linear module M1; another part of the stepped-down current passes through the rectifier bridge D1, through the transistors Q1, Q2, and Q3, and reaches the DC power output terminal.

Among them, the input point of the B end of the high-power linear control module M1 is connected to the base of the transistor Q1, and the emitter of the transistor Q1 is connected to the base of the transistor Q2 and the transistor Q3. The resistor R6 after the transistor Q2 and the transistor Q3 is a sampling resistor. The high-power linear control module M1 collects the current at both ends of the resistor R6 through CS+ and CS- to obtain the output current, and then controls the output voltage of the B end to control the transistor Q1, thereby controlling the output current of the linear power supply.

The working process of the integrated driving circuit in the present invention is as follows:

As shown in FIG3 , the circuit diagram of the high-power linear voltage regulator module M1, the CS+ and CS- terminals sample the output current, and after amplification and conditioning by the operational amplifier U2A, it is given to the operational amplifier U2B through the resistor R20, and compared with the reference voltage values of the input voltage VCC of the high-power linear control module M1, the resistors R11, R12, R13, R14, and R15. Through parameter setting, when the output current reaches the overcurrent point of the linear power supply, the current feedback loop will adjust the operational amplifier U2B to turn on the transistor Q34 to release the pressure, thereby completing the overcurrent protection function under the overcurrent state.

The W1 and W2 ends are connected with an adjustable resistor R41. By adjusting the resistor R41, the bridge voltage composed of resistors R43, R44, R45, R46, R47, R48, R9 and R10 can be fine-tuned and transmitted to the positive ends of the operational amplifiers U3A and U3B through the operational amplifier U1B, and the negative ends of the operational amplifiers U3A and U3B are respectively connected to the reference voltage values output by the resistors R26, R27, R28 and R29. Therefore, the operational amplifiers U3A and U3B correspond to two gears of fine-tunable output voltages respectively, and are finally transmitted to the B-end output of the high-power linear control module M1 through the transistors Q14 and Q24 respectively.

The above disclosure is only a specific embodiment of the present invention, but the present invention is not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims (1)

1. The utility model provides a linear power supply of turn-back type overcurrent protection function, includes alternating current power supply input, steady voltage filter unit, high-power linear control module M1 and DC power supply output, characterized by:

The alternating current power supply input end is electrically connected with the voltage stabilizing and filtering unit;

The voltage stabilizing filter unit is electrically connected with the high-power linear control module M1 and the direct-current power supply output end, and the high-power linear control module M1 is electrically connected with the direct-current power supply output end;

The alternating current power supply input end is used for carrying out safety protection on the alternating current power supply;

The voltage stabilizing and filtering unit is used for carrying out power frequency voltage reduction on an input alternating current power supply, rectifying and filtering, power voltage stabilization and power supply on the high-power linear control module M1;

The high-power linear control module M1 is used for sampling, filtering and comparing the current output by the voltage stabilizing and filtering unit, controlling the voltage stabilizing and filtering unit according to a comparison signal, and finely adjusting the output voltage;

the direct current power supply output end is used for performing polarity protection and overvoltage protection on the direct current power supply;

the input end of the alternating current power supply comprises an L end, an N end and an E end, wherein the L end is electrically connected with one end of a capacitor C1 and a common mode inductor L1, the N end is electrically connected with the other end of the capacitor C1 and the common mode inductor L1, the common mode inductor L1 is electrically connected with two ends of a capacitor C2 and one end of a capacitor C3, the common mode inductor L1 is electrically connected with one end of a switch S1, an anode of a thyristor SR1 and one end of a resistor R1, the other end of the resistor R1 is electrically connected with one end of a capacitor C4, the other end of the switch S1 is electrically connected with one end of a resistor R2, the other end of the resistor R2 is electrically connected with a gate electrode of the thyristor SR1 and one end of a resistor R3, the E end is grounded, and the other end of the capacitor C3 is grounded;

The voltage stabilizing filter unit comprises a transformer T1, the other end of the resistor R3, the other end of the capacitor C4 and the negative electrode of the thyristor SR1 are respectively and electrically connected with the input end of the transformer T1, one output end of the transformer T1 is electrically connected with a rectifier bridge D1, the other output end of the transformer T1 is electrically connected with a rectifier bridge D3, the rectifier bridge D1 is electrically connected with one end of the capacitor C5, the collector of the triode Q1, the collector of the triode Q2 and the collector of the triode Q3, the emitter of the triode Q1 is electrically connected with the base of the triode Q2 and the base of the triode Q3, the emitter of the triode Q2 is electrically connected with a resistor R4, the emitter of the triode Q3 is electrically connected with a resistor R5, and the rectifier bridge D3 is electrically connected with one end of the capacitor C10 and the voltage stabilizing chip U1;

The other end of the capacitor C10 and the voltage stabilizing chip U1 are respectively and electrically connected with the GND end of the high-power linear control module M1, the voltage stabilizing chip U1 is electrically connected with the VCC end of the high-power linear control module M1, the B end of the high-power linear control module M1 is electrically connected with the base electrode of the triode Q1, the CS+ end and the CS-end of the high-power linear control module M1 are respectively and electrically connected with one end of a resistor R6, the W1 end and the W2 end of the high-power linear control module M1 are connected with a rheostat R41, the +S end of the high-power linear control module M1 is grounded, and the-S end and the VOUT-end of the high-power linear control module M1 are connected;

The high-power linear control module M1 comprises a resistor R22 and a resistor R23, wherein one end of the resistor R22 is electrically connected with one end of a capacitor C94, one end of a capacitor C84, one end of a resistor R21 and the reverse input end of an operational amplifier U2A, one end of the resistor R23 is electrically connected with the other end of the capacitor C94, one end of a resistor R24 and the forward input end of the operational amplifier U2A, the other end of the resistor R24 is grounded, the other end of the capacitor C84, the other end of the resistor R21 and the output end of the operational amplifier U2A are respectively electrically connected with one end of a resistor R20, the other end of the resistor R20 is electrically connected with the forward input end of an operational amplifier U2B, one end of the resistor R42 is connected with a capacitor C14, the other end of the resistor R42 is electrically connected with a resistor R11, a resistor R12, the negative electrode of a diode D24, a capacitor C34 and one end of the resistor R16, the capacitor C14, the positive electrode of the diode D24 and the other end of the capacitor C24 are respectively grounded, the other end of the resistor R11 and the other end of the resistor R12 are respectively electrically connected with one end of a resistor R13, the other end of the resistor R13 is electrically connected with one end of a resistor R14, the other end of the resistor R14 is electrically connected with one end of a resistor R15, the other end of the resistor R15 is grounded, the other end of the resistor R11 and the other end of the resistor R12 are respectively electrically connected with the reverse input end of the operational amplifier U2B, the output end of the operational amplifier U2B is electrically connected with one end of a capacitor C74 and one end of a resistor R19, the other end of the capacitor C74 is electrically connected with the reverse input end of the operational amplifier U2B, the other end of the resistor R19 is electrically connected with the base electrode of a triode Q34, the emitter electrode of the triode Q34 is grounded, the collector electrode of the triode Q34 is connected with the end B of the high-power linear control module M1;

The high-power linear control module M1 further comprises a resistor R9, a resistor R10, a resistor R47 and a resistor R48, wherein the other end of the resistor R9 and the other end of the resistor R10 are respectively and electrically connected with the-S end of the high-power linear control module M1, one end of the resistor R47 is electrically connected with one end of the resistor R9, one end of the resistor R48 is electrically connected with one end of the resistor R10, the other end of the resistor R47 is electrically connected with the other end of the resistor R9, the other end of the resistor R48 is electrically connected with the other end of the resistor R10, the other end of the resistor R42 is electrically connected with one end of the resistor R43 and one end of the resistor R44, One end of the resistor R43 is electrically connected with one end of the resistor R44, the other end of the resistor R43 is electrically connected with one end of the resistor R45, the other end of the resistor R44 is electrically connected with one end of the resistor R46, the other end of the resistor R46 is electrically connected with the other end of the resistor R45, the other end of the resistor R45 is electrically connected with the other end of the resistor R47, the other ends of the resistor R45, the resistor R46, the resistor R47 and the resistor R8 are respectively electrically connected with one end of the capacitor C64, the other ends of the capacitor C64 are respectively electrically connected with the W2 end of the high-power linear control module M1, one end of the capacitor C64, the other end of the resistor R45, the other end of the resistor R46, the other end of the resistor R47 and the other end of the resistor R48 are respectively and electrically connected with the negative electrode of the diode D14, the positive electrode of the diode D14 is electrically connected with the +S end of the high-power linear control module M1, the +S end of the high-power linear control module M1 is grounded, the other end of the resistor R45, the other end of the resistor R46, the other end of the resistor R47 and the other end of the resistor R48 are respectively and electrically connected with one end of the capacitor C54, the other end of the capacitor C54 is electrically connected with the-V end of the high-power linear control module M1, The other end of the resistor R43, the other end of the resistor R44, one end of the resistor R45 and one end of the resistor R46 are respectively and electrically connected with the positive input end of the operational amplifier U1A, the other end of the capacitor C34 and the other end of the resistor R16 are respectively and electrically connected with one end of the resistor R17, the other end of the resistor R17 is grounded, the other end of the capacitor C34 and the other end of the resistor R16 are respectively and electrically connected with the negative input end of the operational amplifier U1A, the operational amplifier U1A is electrically connected with one end of the capacitor C44, the other end of the capacitor C44 is grounded, The output end of the operational amplifier U1A is electrically connected with one end of a resistor R18, the other end of the resistor R18 is electrically connected with the collector of the triode Q34 and the end B of the high-power linear control module M1 respectively, the other end of the resistor R43, the other end of the resistor R44, one end of the resistor R45 and one end of the resistor R46 are electrically connected with the forward input end of the operational amplifier U1B respectively, the reverse input end of the operational amplifier U1B is connected with the output end of the operational amplifier U1B, the output end of the operational amplifier U1B is electrically connected with one end of a resistor R25, The other end of the resistor R25 is electrically connected with the forward input end of the operational amplifier U3A and the forward input end of the operational amplifier U3B respectively, the other end of the resistor R42 is electrically connected with one end of the resistor R26, the other end of the resistor R26 is electrically connected with one end of the resistor R27, the other end of the resistor R27 is electrically connected with one end of the resistor R28, one end of the capacitor C11, one end of the capacitor C10 and the reverse input end of the operational amplifier U3A respectively, the other end of the capacitor C11 is electrically connected with the VCC end of the high-power linear control module M1, one end of the capacitor C11 is electrically connected with one end of the resistor R28, One end of the capacitor C10 and the inverting input end of the operational amplifier U3A, one end of the resistor R28 is electrically connected to one end of the capacitor C10 and the inverting input end of the operational amplifier U3A, one end of the capacitor C10 is electrically connected to the inverting input end of the operational amplifier U3A, the inverting input end of the operational amplifier U3B is electrically connected to the other end of the resistor R28, the other end of the capacitor C10 and one end of the resistor R29, the other end of the resistor R29 is grounded, the output end of the operational amplifier U3A is electrically connected to one end of the resistor R31, the other end of the resistor R31 is electrically connected to the base of the transistor Q14, The collector of the triode Q14 is electrically connected with the other end of the resistor R13 and one end of the resistor R14, the emitter of the triode Q14 is grounded, the output end of the operational amplifier U3B is electrically connected with one end of the resistor R30, the other end of the resistor R30 is electrically connected with the base of the triode Q24, the collector of the triode Q24 is electrically connected with the other end of the resistor R14 and one end of the resistor R15, and the emitter of the triode Q24 is grounded;

the DC power supply output end comprises a VOUT+ end and a Vout-end, the rectifier bridge D1, the capacitor C5 and the V-end of the high-power linear control module M1 are respectively and electrically connected with the Vout-end, the other end of the resistor R6 is electrically connected with the VOUT+ end, the VOUT+ end is electrically connected with the overvoltage protection chip M2, one end of the capacitor C6, one end of the capacitor C7, one end of the capacitor C8, one end of the capacitor C9 and the cathode of the diode D2, and the VOUT-end is electrically connected with the overvoltage protection chip M2, the other end of the capacitor C6, the other end of the capacitor C7, the other end of the capacitor C8, the other end of the capacitor C9 and the anode of the diode D2.