CN106602532A - Current limiting circuit, driving method thereof, PMIC protection system and display device protection system - Google Patents

Abstract

The invention provides a current-limiting circuit and its driving method, a PMIC protection system and a display device protection system, belonging to the field of display technology, which can solve the problem that the existing debugging structure cannot be debugged due to the excessive surge current when it is powered on. problem with normal startup. The current limiting circuit of the present invention includes: a current limiting module, a switch module and a charging delay module; the switch module is connected to the first voltage terminal, the charging delay module and the current output terminal; the current limiting module is connected to the first voltage terminal and the current output terminal ; The charging delay module is connected to the first voltage terminal and the second voltage terminal; the current limiting module is used to divide the voltage input by the first voltage terminal during the power-on phase, so as to limit the current output by the current output terminal; The charging delay module is used to provide a turn-on voltage for the switch module after the circuit is turned on for a certain period of time, so as to short-circuit the current limiting module and output a corresponding current through the current output terminal.

Description

Current limiting circuit and its driving method, PMIC protection system and display device protection system

technical field

The invention belongs to the field of display technology, and in particular relates to a current limiting circuit, a driving method thereof, a PMIC protection system and a display device protection system.

Background technique

Manufacturers need to develop and debug the performance of the display device before selling the display device to the majority of users. The commonly used debugging structure is to connect the voltage input terminal to the input terminal of the Power Management IC (PMIC). The output terminal is connected to the display device.

In the development and debugging stage of the display device, a surge current will be generated in the debugging circuit. The surge current refers to the peak current flowing into the power supply device at the moment when the power is turned on. The current value of the surge current is much greater than the steady-state normal The current value of the current. When the voltage is input, a surge current is generated immediately and the current value of the surge current increases gradually. When the current value of the surge current increases to the peak value, it begins to decrease, and finally reaches the current value of the normal current.

The inrush current generated during the R&D and debugging stage sometimes occurs because the inrush current generated during power-on (that is, the input voltage of the voltage input terminal) is too large, causing the PMIC to burn out or the inrush current is detected as a large current to initiate a short circuit Protection phenomenon, which prevents the debug structure from starting normally. But for this phenomenon, there is no effective measure to solve it.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a current-limiting circuit and its driving method that can reduce the surge current at power-on to avoid the normal start-up of the debugging structure caused by the surge current , PMIC protection system and display device protection system.

The technical solution adopted to solve the technical problem of the present invention is a current limiting circuit, including: a current limiting module, a switch module and a charging delay module;

The switch module is connected to the first voltage terminal, the charging delay module and the current output terminal;

The current limiting module is connected to the first voltage terminal and the current output terminal;

The charging delay module is connected to the first voltage terminal and the second voltage terminal;

The current limiting module is configured to divide the voltage input by the first voltage terminal during the power-on phase, so as to limit the current output by the current output terminal;

The charging delay module is used to provide a turn-on voltage for the switch module after the circuit is turned on for a certain period of time, so as to short-circuit the current limiting module and output a corresponding current through the current output terminal.

Wherein, the switch module includes a switch tube, the first pole of the switch tube is connected to the first voltage terminal, the second pole of the switch tube is connected to the current output terminal, and the control pole of the switch tube Connect with the charging delay module.

Wherein, the current limiting module includes a first resistor, the first end of the first resistor is connected to the first voltage end, and the second end of the first resistor is connected to the current output end.

Wherein, the charging delay module includes a capacitor and a second resistor, the first end of the second resistor is connected to the first voltage end, the second end of the second resistor is connected to the first end of the capacitor connected, the second end of the capacitor is connected to the second voltage end.

As another technical solution, the present invention also provides a driving method for a current limiting circuit, including:

Power-on stage: input the first power supply voltage to the first voltage terminal, charge the charging delay module, turn off the switch module, and divide the first power supply voltage input by the first voltage terminal through the current limiting module to limit the current The magnitude of the current output by the output terminal;

The stage of current output: through the charging delay module, the switch module is provided with a turn-on voltage, the switch module is turned on, the current limiting module is short-circuited, and the current output terminal outputs a corresponding current.

As another technical solution, the present invention also provides a PMIC protection system, including the current limiting circuit described in any one of the above.

Wherein, the PMIC protection system also includes a power management integrated circuit;

The power management integrated circuit is electrically connected to the current output terminal of the current limiting circuit.

As another technical solution, the present invention also provides a display device protection system, including the PMIC protection system described in any one of the above, a second current limiting circuit and a display device connected in sequence, the structure of the second current limiting circuit The structure is the same as that of the current limiting circuit described in any one of the above.

Wherein, the output terminal of the power management integrated circuit in the PMIC protection system is the first voltage terminal of the second current limiting circuit, and the current output terminal of the second current limiting circuit is electrically connected to the display device.

In the current limiting circuit and its driving method, PMIC protection system and display device protection system of the present invention, the current limiting circuit includes: a current limiting module, a switch module and a charging delay module, the switch module is connected to the first voltage terminal, the charging delay module and the current output terminal, the current limiting module is connected to the first voltage terminal and the current output terminal, and the charging delay module is connected to the first voltage terminal and the second voltage terminal, wherein the current limiting module can control the voltage of the first voltage terminal during the power-on stage The input voltage is divided to limit the magnitude of the current output by the current output terminal, and then after the current limiting circuit is turned on for a certain period of time, the charging delay module provides the switch module with a turn-on voltage to short-circuit the current limiting module, and The corresponding current is output through the current output terminal, and the current at this time is a normal current, so as to avoid the problem that the debugging structure cannot be started normally due to the surge current.

Description of drawings

Fig. 1 is the structural representation of the current limiting circuit of embodiment 1 of the present invention;

Fig. 2 is the specific structural schematic diagram of the current limiting circuit of embodiment 1 of the present invention;

3 is a schematic flowchart of a driving method of a current limiting circuit according to Embodiment 2 of the present invention;

Fig. 4 is the structural representation of the PMIC protection system of embodiment 3 of the present invention;

5 is a schematic structural diagram of a display device protection system according to Embodiment 4 of the present invention;

Wherein, reference signs are: 1. current limiting module; 2. switch module; 3. charging delay module; VCC, first voltage terminal; OUT, current output terminal; VSS, second voltage terminal; T, switch tube; Rs, the first resistance; Ct, the capacitance; Rt, the second resistance.

detailed description

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

Please refer to Figure 1 and Figure 2, this embodiment provides a current limiting circuit, including: a current limiting module 1, a switch module 2 and a charging delay module 3; the switch module 2 is connected to the first voltage terminal VCC and the charging delay module respectively 3 is connected to the current output terminal OUT; the current limiting module 1 is connected to the first voltage terminal VCC and the current output terminal OUT; the charging delay module 3 is respectively connected to the first voltage terminal VCC and the second voltage terminal VSS; the current limiting module 1 It is used to divide the voltage input by the first voltage terminal VCC during the power-on phase to limit the current output by the current output terminal OUT; 2 provides a turn-on voltage to short-circuit the current limiting module 1 and output a corresponding current through the current output terminal OUT.

It should be noted that, in this embodiment, the second voltage terminal VSS is at a lower potential than the first voltage terminal VCC, and the second voltage terminal VSS can also be grounded, which will not be repeated here.

Since the current limiting module 1 is set in the current limiting circuit in this embodiment, the current limiting module 1 divides the voltage input by the first voltage terminal VCC during the power-on phase, that is, the current limiting phase, so that the current output The output current of the terminal OUT is smaller than the peak value of the surge current. At the same time, after a certain period of time, the charging delay module 3 provides a turn-on voltage for the switch module 2 to turn on the switch module 2, so that the current limiting module 1 is short-circuited, thereby ensuring normal current output from the current output terminal OUT.

Please refer to FIG. 2 , wherein, the switch module 2 includes a switch tube T, the first pole of the switch tube T is connected to one end of the current limiting module 1, the second pole of the switch tube T is connected to the other end of the current limiting module 1, and the switch tube The control pole of T is connected with the charging delay module 3 .

In this embodiment, the switching tube T is an N-type transistor, the first pole is the source of the N-type transistor, the second pole is the drain of the N-type transistor, and the control pole is the gate of the N-type transistor. When the gate is input with a high level, Source-drain conduction. Certainly, the type of the switching transistor T is not limited thereto, and a P-type transistor may also be used, which is opposite to an N-type transistor, so details will not be repeated here.

Wherein, the current limiting module 1 includes a first resistor Rs, the first terminal of the first resistor Rs is connected to the first voltage terminal VCC, and the second terminal of the first resistor Rs is connected to the current output terminal OUT.

It should be noted that the resistance of the first resistor Rs needs to be calculated in advance, for example, the resistance of the first resistor Rs is calculated according to the input voltage of the first voltage terminal VCC and the current value of the normal current. Of course, in this embodiment, as long as the current limiting module 1 is installed, the purpose of dividing the voltage input from the first voltage terminal VCC to reduce the current value of the surge current can be realized, but only when the resistance of the first resistor Rs When the value is the ratio of the voltage input by the first voltage terminal VCC to the current value of the normal current, the current output by the current output terminal OUT in the power-on phase can be equal to the normal current; at the same time, it is also necessary to obtain the surge current. The time range, wherein, the time range in which the surge current occurs corresponds to the time when the delay switch module 2 needs to be turned on by the charging delay module 3 . Since the acquisition method of the resistance value of Rs and the time range of the surge current can adopt the existing technology, it will not be repeated here.

Wherein, the charging delay module 3 includes a capacitor Ct and a second resistor Rt, the first end of the second resistor Rt is connected to the first voltage terminal VCC, the second end of the second resistor Rt is connected to the first end of the capacitor Ct, and the capacitor The second end of Ct is connected to the second voltage end VSS.

It should be noted that the resistance value of the second resistor Rt and the voltage of the capacitor Ct can be calculated according to the time range in which the surge current occurs, which will not be repeated here.

The specific current limiting principle of the current limiting circuit of this embodiment is:

In the power-on stage, that is, the current-limiting stage, the input voltage of the first voltage terminal VCC, the second resistor Rt and the capacitor Ct form an RC delay circuit, so that the switch tube T cannot be turned on immediately at the moment of power-on; at the same time, the first resistor Rs and the RC delay circuit divide the input voltage of the first voltage terminal VCC to limit the magnitude of the current output by the current output terminal OUT, so that the output current at this time is smaller than the surge current output by the existing debugging circuit Peak.

In the current output stage, the voltage input by the first voltage terminal VCC charges the capacitor Ct for a certain period of time (that is, the time for the surge current to decrease to the normal current), and reaches the threshold voltage (turn-on voltage) of the switch tube T, and the switch tube T is turned on. At this time, the first resistor Rs is short-circuited, and the circuit enters a normal working state, that is, the current at this time is a normal current.

The current limiting circuit of this embodiment includes: a current limiting module 1, a switch module 2 and a charging delay module 3; the switching module 2 is connected to the first voltage terminal VCC, the charging delay module 3 and the current output terminal OUT, and the current limiting module 1 Connect the first voltage terminal VCC and the current output terminal OUT, and the charging delay module 3 is connected to the first voltage terminal VCC and the second voltage terminal VSS, wherein the current limiting module 1 can control the input voltage of the first voltage terminal VCC during the power-on phase. The voltage is divided to limit the current (i.e. surge current) output by the current output terminal OUT, and then after the current limiting circuit is turned on for a certain period of time, the charging delay module 3 provides the switch module 2 with a turn-on voltage, so that The current limiting module 1 is short-circuited and outputs the corresponding current through the current output terminal OUT. The current at this time is a normal current to avoid the problem that the debugging structure cannot be started normally caused by the inrush current; at the same time, because the structure of the current limiting circuit is simple , therefore, the cost of the current limiting circuit is low and the applicability is strong.

Example 2:

Please refer to FIG. 3. This embodiment provides a driving method of a current limiting circuit, which is used to drive the current limiting circuit of Embodiment 1. The driving method includes:

Power-on stage: input the first power supply voltage to the first voltage terminal, charge the charging delay module, turn off the switch module, and divide the first power supply voltage input to the first voltage terminal through the current limiting module to limit the current output terminal The magnitude of the output current.

In the stage of current output: the switch module is provided with a turn-on voltage through the charging delay module, the switch module is turned on, the current limiting module is short-circuited, and the current output terminal outputs a corresponding current.

The driving method of the current-limiting circuit of this embodiment is used to drive the current-limiting circuit of Embodiment 1. For a detailed description, refer to the current-limiting circuit of Embodiment 1, which will not be repeated here.

In the driving method of the current limiting circuit in this embodiment, the current limiting module can divide the voltage input by the first voltage terminal during the power-on phase to limit the current (ie surge current) output by the current output terminal, and then After the current limiting circuit is turned on for a certain period of time, the charging delay module provides a turn-on voltage for the switch module to short-circuit the current limiting module, and outputs a corresponding current through the current output terminal. The current at this time is a normal current to avoid waste The problem that the debugging structure cannot start normally caused by the inrush current.

Example 3:

Referring to FIG. 4 , this embodiment provides a PMIC protection system, including the current limiting circuit of Embodiment 1.

Wherein, the PMIC protection system also includes a power management integrated circuit (namely PMIC); the power management integrated circuit is electrically connected to the current output terminal of the current limiting circuit.

That is to say, the normal current output from the current limiting circuit directly enters the PMIC. Since the current limiting circuit can avoid the surge current and output the normal current, it can prevent the PMIC from being damaged by the surge current or being detected as a large current. There is a phenomenon that the short circuit protection is activated.

The PMIC protection system of this embodiment includes the current limiting circuit of Embodiment 1, the surge circuit can be avoided through the current limiting circuit, and the normal current is input into the PMIC, thereby protecting the PMIC and preventing the PMIC from being damaged or detected by the surge current The phenomenon of starting short-circuit protection is caused by high current.

Example 4:

Please refer to Fig. 5, this embodiment provides a display device protection system, including the PMIC protection system of embodiment 3, the second current limiting circuit and the display device connected in sequence, the structure of the second current limiting circuit is the same as that of embodiment 1. The flow circuit has the same structure.

It should be noted that the structure of the second current-limiting circuit is the same as that of the current-limiting circuit in Embodiment 1, but the structural labels in FIG. 5 are different, which are only for distinction and will not be repeated here.

Wherein, the output terminal of the power management integrated circuit in the PMIC protection system is the first voltage terminal of the second current limiting circuit, and the current output terminal of the second current limiting circuit is electrically connected to the display device.

The reason why there is a current circuit between the PMIC protection system and the display device is that the current input to the PMIC is not necessarily equal to the output current of the PMIC. When the system is powered on, a peak current (peak current) will also be generated in the PMIC. greater than the normal current), if the current output from the PMIC is directly input into the display device, the display device will be damaged. Therefore, adding a second current limiting circuit between the PMIC and the display device can reduce the output current of the PMIC, In order to reduce the surge current received by the display device, that is, the load, the display device is effectively protected from being damaged by the peak current.

The display device protection system of this embodiment includes the PMIC protection system of Embodiment 3 and the current-limiting circuit of Embodiment 1. For detailed description, refer to the current-limiting circuit of Embodiment 1 and the PMIC protection system of Embodiment 3, which will not be repeated here. .

The display device protection system of this embodiment can reduce the output current of the PMIC to reduce the inrush current received by the load of the display device, thereby effectively protecting the display device from being damaged by the peak current.

It can be understood that, the above embodiments are only exemplary embodiments adopted for illustrating the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (9)

1. a kind of current-limiting circuit, it is characterised in that include：Current limliting module, switch module and charging time delay module；

The switch module connection first voltage end, charging time delay module and current output terminal；

The current limliting module connects the first voltage end and the current output terminal；

The charging time delay module connects the first voltage end and second voltage end；

The current limliting module, for carrying out partial pressure to the voltage that the first voltage end is input in power up phase, to limit State the size of current that current output terminal is exported；

The charging time delay module, for after the circuit turn-on certain hour, for the switch module cut-in voltage being provided, So that the current limliting module short circuit, and corresponding electric current is exported by the current output terminal.

2. current-limiting circuit according to claim 1, it is characterised in that the switch module includes switching tube, the switch First pole of pipe is connected with the first voltage end, and the second pole of the switching tube is connected with the current output terminal, described to open The control pole for closing pipe is connected with the charging time delay module.

3. current-limiting circuit according to claim 1, it is characterised in that the current limliting module includes first resistor, described the The first end of one resistance is connected with the first voltage end, and the second end of the first resistor is connected with the current output terminal.

4. current-limiting circuit according to claim 1, it is characterised in that the charging time delay module includes electric capacity and second electric Resistance, the first end of the second resistance is connected with the first voltage end, the second end and the electric capacity of the second resistance First end connects, and the second end of the electric capacity is connected with the second voltage end.

5. a kind of driving method of current-limiting circuit, it is characterised in that include：

Power up phase：The first supply voltage is input into for first voltage end, is that charging time delay module charges, switch module is closed, and is led to Cross current limliting module carries out partial pressure to the first supply voltage that the first voltage end is input into, to limit what current output terminal was exported Size of current；

The stage of electric current output；Cut-in voltage is provided for switch module by the charging time delay module, switch module is opened, limit Flow module short circuit, the current output terminal exports corresponding electric current.

6. a kind of PMIC protection systems, it is characterised in that including the current-limiting circuit described in Claims 1-4 any one.

7. PMIC protection systems according to claim 6, it is characterised in that also including power management integrated circuit；

The power management integrated circuit is electrically connected with the current output terminal of the current-limiting circuit.

8. a kind of display apparatus protecting system, it is characterised in that protect including the PMIC described in the claim 6 or 7 being sequentially connected Protecting system, the second current-limiting circuit and display device, structure and the Claims 1-4 any one institute of second current-limiting circuit The structure of the current-limiting circuit stated is identical.

9. display apparatus protecting system according to claim 8, it is characterised in that the power supply in the PMIC protection systems The output end of management integrated circuit is the first voltage end of second current-limiting circuit, and the electric current of second current-limiting circuit is exported End electrically connects with the display device.