KR0181922B1 - Power circuit of partial vacuum type controlled by one pwm pulse - Google Patents

Abstract

The present invention relates to a voltage step-down power supply circuit of the partial resonant method to minimize the power loss in the voltage step-down power supply circuit, the circuit configuration to be controlled by one PWM pulse. Particularly in the voltage resonant power supply circuit of the DC voltage generator, the voltage step-up part composed of the juice switching part and the auxiliary switch part, and the control part, it is possible to replace the conventional control part by only one PWM pulse. Connect the PWM controller, the time delay and the trigger generator with the drive transformer to control the switching unit and the auxiliary switching unit at the same time, and control the juice switching element according to the time delayed PWM pulse and the auxiliary switching element according to the generated trigger pulse. By providing a control unit for controlling, the power loss of the voltage step-down power supply circuit can be minimized and the circuit configuration can be made simpler.

Description

Partial resonance type voltage step-down power circuit controlled by one PWM pulse

The present invention relates to a voltage resonant power supply circuit of a partial resonance method for improving power loss, and more particularly, to a voltage resonant power supply of a partial resonance method in which both the juice switching unit and the auxiliary switching unit are controlled by one PWM pulse. It is about a circuit.

In general, electronic devices such as televisions, computers, and monitors use voltage step-down power supply circuits to provide DC power supply values required for each part of the system. This voltage step-down power supply circuit converts and outputs a power source of unstable alternating current (AC) or direct current (DC) voltage to a constant direct current (DC) voltage, an example of which is shown in FIG.

1 is a circuit diagram showing a conventional voltage step-down power supply circuit. As shown in the drawing, the conventional voltage step-down power supply circuit receives a power supply Vin of AC or DC voltage and has a rectifying function for generating a DC voltage V1. ), And a control unit 130 for controlling the voltage step-down unit 120 by receiving a voltage step-down unit 120 and an output voltage Vout for obtaining a desired output voltage Vout from the generated DC voltage V1. do. Here, the voltage step-down unit 120 is a field effect transistor (FET) and a field effect transistor (FET) which is a switching element that is driven "on / off" by the pulse signal output from the control unit 130, Power accumulation coil L1 that accumulates the power of the DC voltage V1 generated from the DC voltage generator 110 and the field effect transistor FET in the ON state. And a flywheel diode D1 conducted according to the counter electromotive force of the power accumulation coil L1, and a capacitor C1 discharging the accumulated power to output a desired voltage Vout.

When an AC voltage is input to the conventional voltage step-down power supply circuit configured as described above, the DC voltage generating unit 110 rectifies the power to generate a DC voltage V1, and when the DC voltage is input, it remains as it is. Output The DC voltage V1 generated by the DC voltage generator 110 is input to the voltage step-down unit 120. The field effect transistor (FET), which is a switching element of the voltage step-down unit 120, is repeatedly “ON / OFF” in response to a pulse signal output from the controller 130 to switch the DC voltage input. Here, the controller 130 receives the output voltage (Vout) of the voltage step-down unit 120 and monitors whether the desired voltage is output. That is, the PWM controller 131 receives the output voltage Vout and changes the width of the pulse signal output to the field effect transistor (FET) driver 132 to output the DC voltage required in the system in a stable state without change. Be sure to The field effect transistor (FET) driver 132 drives the field effect transistor (FET), which is a switching element of the voltage step-down unit 120, according to an input PWM pulse to turn on / off.

On the other hand, when the field effect transistor FET is "ON", the input DC voltage V1 is accumulated in the power storage coil L1. When the field effect transistor FET is "OFF", the input DC voltage V1 is cut off, and the flywheel diode is conducted by the counter electromotive force of the power accumulation coil L1. Then, the power accumulated in the power accumulation coil L1 is discharged from the capacitor C1 to obtain a desired output voltage Vout. At this time, the output voltage Vout depends on the pulse width of the PWM pulse signal output from the DC voltage V1 generated by the DC voltage generator 110 and the field effect transistor (FET) driver 132 of the controller 130. Is determined.

However, when the field effect transistor (FET), which is a switching element, is switched on or off in the conventional voltage step-down power supply circuit as described above, a large power loss occurs and the efficiency of the power supply circuit is lowered. A lot of heat is generated in the switching device. Therefore, the size of the heat dissipation or cooling system attached to the switching element in order to emit heat has a problem that the size of the overall power circuit is increased.

On the other hand, the partial resonant voltage step-down type power supply circuit is a circuit method proposed to solve the above problems of the conventional voltage step-down type power supply circuit, and its configuration and operation principle will be described with reference to FIG. .

The partial resonance type voltage step-down power supply circuit receives a direct current (DC) voltage generation unit that receives a direct current (AC) or a direct current (DC) voltage as an input and generates a direct current (DC) voltage, and receives a constant output voltage and responds thereto. A control unit that outputs a pulse width modulated (PWM) pulse signal of a pulse width, and a voltage step-down unit for stepping down a DC voltage generated according to the pulse width of the pulse signal to obtain a desired output voltage. In the conventional voltage step-down section 120, the current direction setting diodes (D2, D3), the resonant capacitor (C2), another switching element field effect transistor (FET2) and the resonant coil (L2) by adding A voltage resonating unit 220 of a partial resonance method is configured. In addition, a time delay unit 232 for outputting a delayed PWM pulse of the PWM controller 231 by a predetermined time to the control unit 130, and the first juice switching element of the voltage step-down unit 220 according to the time delayed PWM pulse. The first FET driver 233 for driving the field effect transistor FET1, the trigger pulse generator 234 for generating the trigger pulse at the rising edge of the PWM pulse, and the second field effect transistor as the auxiliary switching element according to the trigger pulse (FET2). The control unit 230 is configured by adding a second FET driver 235 driving.

The operation of the voltage step-down power supply circuit of the partially resonant type structure configured as described above will be described in more detail with reference to FIG. 3, which is a timing diagram of the main part of the circuit of FIG. 2. If the input power Vin is an AC power, it is rectified to output a DC voltage V1, and if the input power Vin is a DC power, it is output as it is. The DC voltage V1 generated by the DC voltage generator 210 is input to the voltage step-down part 220 of the partial resonance method. The voltage resonator 220 of the partial resonant method outputs a DC voltage input under a control of the controller 230 as a constant voltage. In the controller 230, the PWM controller 231 receives the output voltage Vout of the voltage step-down part 220 and generates a PWM pulse having a pulse width corresponding thereto (see FIG. 3A). The time delay unit 232 receives the PWM pulse of FIG. 3A and delays it for a predetermined time (t0 to t1) and outputs it to the first FET driver 233 (see FIG. 3B). The first FET driver 233 “ONs” the first field effect transistor FET1, which is the juice switching element, in the high potential section of the time delayed PWM pulse of FIG. 3B, and “OFF” in the low potential section. Let's do it. In addition, the trigger pulse generator 234 generates a trigger pulse at the rising edge of the PWM pulse of FIG. 3A (see also FIG. 3C). The second FET driver 235 “ONs” the second field effect transistor FET2 which is the booth switching element in the high potential section of the trigger pulse of FIG. 3C and “OFFs” in the low potential section.

In the meantime, the voltage step-down part 220 of the partial resonant method operates in the same manner as the voltage step-down part 120 of FIG. 1 in the section in which the first field effect transistor FET1 is in the "ON" state. That is, the direct current (DC) voltage V1 generated by the direct current (DC) voltage generator 210 is accumulated in the first coil L1 of the transformer T1. On the other hand, in the section in which the first field effect transistor FET1 is in the "OFF" state, the current I1 flowing through the first field effect transistor FET1 is cut off (see also (D) of FIG. 3), The counter electromotive force is generated in the first coil L1 to output the accumulated voltage. Here, the voltage at the source side of the first field effect transistor FET1 is drastically lowered at a predetermined time period t1 to t2 when the first field effect transistor FET1 is in the "off" state. Thus, a potential difference is rapidly generated at both ends of the resonant capacitor C2, and the resonant current I3 flows through the current direction setting diode D2 to the capacitor C2 as shown in FIG. The capacitor C2 is charged, and at this time, the first current I1 of the first field effect transistor FET1, which is the juice switching element, becomes “0” (see FIG. 3D). Just before the first field effect transistor FET1, which is the juice switching element, is turned “ON,” the second field effect transistor FET2, which is the booth switching element, is held for a predetermined time (t3 to t5) by the trigger pulse of FIG. 3C. Will be turned “ON”. At this time, the resonant current I4 flows through the current direction setting diode D3 to the second coil and the second field effect transistor FET2 of the transformer T1 as shown in FIG. 3F, and thus the charging voltage of the resonant capacitor C2. Discharge. As a result, counter electromotive force is generated in the first coil L1 of the transformer T1 to suppress the second current I2 flowing in the flywheel diode D1 (see FIG. 3G), and The first current I1 of the first field effect transistor FET1 is suppressed (see also FIG. 3D). Thus, at the time when the first field effect transistor FET1, which is the juice switching element, is turned "ON / OFF", the current I1 becomes "0" state (see FIG. 3D). Minimize the power loss that occurs when “on / off”. At this time, the current I5 flowing to the output side is shown in FIG. 3H.

The voltage resonant power supply circuit of the partial resonant method as described above solves the problems of the conventional voltage step-down power supply circuit, improving efficiency and minimizing the generation of heat, but the pulse switching circuit driving pulse pulse circuit and the auxiliary switching unit trigger The circuit is complicated because the pulse generator is configured separately and the frequency of the PWM module is locked to the trigger pulse generator.

An object of the present invention is to configure a circuit in which the juice switching unit and the auxiliary switching unit are controlled simultaneously by one PWM pulse, so that one PWM pulse can further simplify the construction of a conventional voltage resonant power supply circuit of a partial resonance method. It is to provide a voltage step-down power supply circuit of the partial resonance method controlled by.

1 is a circuit diagram showing a conventional voltage step-down power supply circuit;

2 is a schematic diagram of a voltage resonant type power supply circuit of a partial resonance method for improving power loss;

3 is a timing diagram of an important driver of FIG. 2;

4 is a detailed view showing an embodiment of a voltage step-down power supply circuit of a partial resonance type controlled by one PWM pulse to which the present invention is applied;

5 is a timing diagram of an important driver of FIG. 4.

* Explanation of symbols for main parts of the drawings

Vin: Input voltage (AC or DC)

V1: Output voltage of DC voltage generator

Vout: Output voltage L1, L11: Power accumulation coil

110,220,410: DC voltage generator

L2, L12: resonance coil 120: voltage step-down part

C1: Output voltage discharge capacitor

220,420: Voltage step-down part of resonant method

C2: resonance capacitor 221,421: auxiliary switching unit

D1: Flywheel Diode

222,422 Juice Juicer

D2, D3: diode for current direction setting

130,230,430: control unit T1: transformer

131,231,431: PWM controller C33: time delay capacitor

132: FET driver R31, R32, R33, R34: resistor

232,432: Time delay C31, C32: Capacitor

233,433: 1st FET driver D31, D32: diode

234: trigger pulse generator Q31: transistor

235: second FET driver T2: drive transformer

434: trigger generation and the second FET driver

L21: Primary coil of drive transformer

FET: Field Effect Transistor

L22: Coil for Juice Switching Element

FET1: first field effect transistor

L23: Coil for Auxiliary Switching Element

FET2: second field effect transistor

The characteristics of the voltage step-down power supply circuit of the partial resonant method controlled by one PWM pulse according to the present invention for achieving the above object is a partial resonance having a direct current (DC) voltage generator, voltage step-down unit and PWM control unit In the voltage step-down power supply circuit of the system, a control circuit is provided so that the juice switching unit and the auxiliary switching unit can be simultaneously controlled by one PWM pulse.

Hereinafter, with reference to the accompanying drawings a preferred embodiment of the voltage step-down power supply circuit of the partial resonant method controlled by one PWM pulse according to the present invention will be described in detail. As shown in FIG. 4, the voltage resonant type power supply circuit of a partial resonance type controlled by one PWM pulse receives an alternating current (AC) or a direct current (DC) voltage as an input and generates a direct current (DC) voltage. The voltage generator 410, a time delay unit 432 for outputting a delayed PWM pulse of the PWM controller 431 by a predetermined time, and a first juice switching element of the voltage step-down unit 420 according to the time delayed PWM pulse. A first FET driver 433 for driving the field effect transistor FET1, a trigger pulse generator for generating a trigger pulse at the rising edge of the PWM pulse, and a second field effect transistor FET2, which is an auxiliary switching element, according to the trigger pulse. A control unit 430 including a second FET driver 434 and receiving a constant output voltage and outputting a pulse width modulated (PWM) pulse signal having a corresponding pulse width; and diodes D2 and D3 for current direction setting. Capacitor (C2), 2nd field effect transformer It includes a jitter (FET2), a resonant coil (L12), a first field effect transistor (FET1), a power storage coil (L11), a flywheel diode (D1), and an output voltage discharge capacitor (C1). The voltage step-down part 420 obtains a desired output voltage by stepping down the DC voltage generated according to the pulse width.

The partial resonant voltage step-down power supply circuit controlled by one PWM pulse configured as described above is the same in structure and operation as the conventional partial resonant type voltage step-down power supply circuit, and the juice switching part and the auxiliary switching part Since only a part of the circuit components of the controller to be controlled by the PWM pulses is different, a more detailed description will be given with reference to the detailed view 4 and the timing diagram thereof. Is inputted as a direct current (DC) voltage through the direct current (DC) voltage generator 410 to the voltage step-down section 420, the first field effect transistor (FET1), the flywheel (flywheel) of the juice switching unit 422 The output voltage Vout is obtained by the diode D1, the power storage coil L11, and the capacitor C1 for output voltage discharge, and is assisted just before the first field effect transistor FET1 is “ON”. The switching unit 421 conducts and resonates The series of operations in which the resonance current flows by the capacitor C2, the current direction diode D3, the resonance coil L12, and the second field effect transistor FET2 are conventional voltage resonant type. It is the same as the power supply circuit and is described in detail in the technical field to which the invention belongs and the prior art in that field.

In FIG. 4, when one PWM pulse (see FIG. 5A) is applied to the primary side coil L21 of the drive transformer T2 (see FIG. 5B) by the PWM pulse generator 431 (see FIG. 5B), the secondary side coil of the drive transformer T2. PWM pulses are induced at (L22 and L23). At this time, the induced voltage of the juice switching element coil (L22) by the time delay capacitor (C33) as shown in Figure 5c It will be delayed by t (t1 ~ t2). In addition, since the auxiliary switching element coil L23 of the driving transformer T2 has no delay element, the auxiliary switching element coil L23 is induced as shown in FIG. 5E in the same phase as the PWM pulse. The first field effect transistor FET1, which is a juice switching element, is controlled by the first FET driver 433, and the gate voltage (see FIG. 5D). It is supplied by the resistor R31 and the diode D31 during the high potential period of the PWM pulse (see FIG. 5C) delayed by t, and discharged by the transistor Q31 and the resistor R31 during the low potential period.

On the other hand, the phase is higher than the driving PWM pulse of the first field effect transistor FET1 induced in the auxiliary switching element coil L23. The PWM pulse (see FIG. 5E) preceding t is generated by the charge / discharge circuit composed of the series circuits of the resistors R34 and R35 and the capacitor C32 in a short time to generate the charge and discharge current across the capacitor C32. Accordingly, the gate voltage of the second field effect transistor FET2, which is an auxiliary switching element, across the resistor R35 is generated with a short trigger voltage during t1 to t2 as shown in FIG. 5F. Therefore, in the second field effect transistor FET2, the first field effect transistor FET1 is “ON”. After the short period of time (t2 to t3) that the first field effect transistor (FET1) is conducted (t2) before the t period, the auxiliary switching unit 421 is partially resonated (oscillation). Will be

As a result, in the juice switching unit 422, the PWM pulse generated by the PWM pulse generating unit, the time delay unit 432, and the first FET driver 433 are used. The PWM pulse delayed by t generates the output voltage Vout by controlling the first field effect transistor FET1, which is the juice switching element, "on / off" by a constant pulse width Duty. In addition, the auxiliary switching unit 421 assists immediately before the first field effect transistor FET1, which is the juice switching element of the juice switching unit 422, is turned on by the trigger generation and the second FET driver 434. The second field effect transistor FET2, which is a switching element, is operated, and charges charged in the resonant capacitor C2 immediately after “OFF” of the first field effect transistor FET1 are transferred to the resonant capacitor C2. ), And discharge by the current direction setting diode D3 and the resonance coil L12 (see also FIG. 3F).

This allows the current flowing in the juice switching element FET1 to be in a "0" state when the juice switching element FET1 is "ON" or "OFF", and the power loss problem during switching. Improves.

According to the partial resonance type voltage step-down power supply circuit controlled by one PWM pulse according to the present invention as described above, the juice switching unit and the auxiliary switching unit of the conventional partial resonance type voltage step-down power supply circuit are one PWM. The circuit configuration can be made simpler by allowing pulse control.

Claims (2)

The DC voltage generator generates a DC voltage by receiving AC or DC voltage, and outputs a PWM pulse having a pulse width corresponding to the feedback of a constant output voltage. It includes a control unit that drives the juice switching unit and the auxiliary switching unit, and an auxiliary switching unit for the juice switching unit and the partial resonance, and outputs a constant voltage by stepping down the DC voltage input according to the pulse width of the PWM pulse. In the partial resonance type voltage step-down power supply circuit for improving the power loss problem composed of a voltage step-down part, Partial resonance type voltage step-down power supply circuit controlled by one PWM pulse, characterized in that it comprises a control unit for controlling the juice switching unit and the auxiliary switching unit with one PWM pulse. The method according to claim 1, wherein the control unit, A PWM pulse generator for generating a PWM pulse by receiving a DC output voltage, a drive transformer for simultaneously transferring the PWM pulses generated by the PWM pulse generator to a time delay, a trigger generator, and a second FET driver; A time delay unit for time-delaying the PWM pulse transmitted by the drive transformer, a first FET driver for controlling the juice switching element according to the PWM pulse time-delayed by the time delay unit, and a PWM pulse signal transmitted by the drive transformer Partial resonance type voltage step-down power supply circuit for generating a trigger pulse and controlled by one PWM pulse, characterized in that it comprises a trigger generation and a second FET driver for controlling the auxiliary switching element in accordance with the generated trigger pulse.