Input voltage protection circuit of control chip VDD and driving power supply

Abstract

The utility model relates to an input voltage protection circuit of a control chip VDD and a driving power supply. The input voltage protection circuit comprises an input under-voltage protection circuit and an input over-voltage protection circuit. The input under-voltage protection circuit comprises a first voltage detection module, a first comparison operation module and a first switch control module; the input overvoltage protection circuit comprises a second voltage detection module, a second comparison operation module and a second switch control module. According to the utility model, the input voltage is detected through the first voltage detection module and the second voltage detection module and is compared with the first reference signal and the second reference signal through the first comparison operation module and the second comparison operation module; and then the first switch control module and the second switch control module respectively control the on-off of the power supply of the control chip, so that the control chip does not work when the input is under-voltage, and the purpose of input under-voltage protection is achieved. And when overvoltage is input, the control chip does not work, and the purpose of input overvoltage protection is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of driving power supplies, and more specifically, to an input voltage protection circuit for controlling a chip VDD and a driving power supply. Background Art

[0002] In the field of driver power supplies, such as LED driver power supplies, there is basically no overvoltage protection or undervoltage protection for the input voltage, or some solutions have adopted overvoltage or undervoltage protection, but the current solutions have complex circuit structures and high costs.

[0003] However, if the input voltage is not detected and protected against overvoltage or undervoltage, the following problems will occur: For example, the current driver power supply on the production line does not have input voltage detection and protection during the aging test. When there is overvoltage, the driver power supply is easily damaged (such as explosion) during the aging process. For example, if the target design voltage is 277V, and the actual input voltage is 300V, if the input voltage is not detected at this time, the driver power supply will be damaged when used for a long time. When the input voltage is undervoltage, such as the target design voltage is 200V, but the actual input voltage is only 100V, it is very easy to generate too much heat when used for a long time, and the driver power supply will be too hot and burn out. Therefore, it is necessary to detect and protect the input voltage of the driver power supply. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide an input voltage protection circuit and a driving power supply for controlling the VDD of a chip.

[0005] The technical solution adopted by the utility model to solve the technical problem is: constructing an input voltage protection circuit for controlling the VDD of a chip, including: an input undervoltage protection circuit and an input overvoltage protection circuit;

[0006] The input undervoltage protection circuit includes: a first voltage detection module, a first comparison operation module and a first switch control module; the input overvoltage protection circuit includes: a second voltage detection module, a second comparison operation module and a second switch control module;

[0007] The input end of the first voltage detection module is connected to the AC input end, the output end of the first voltage detection module is connected to the input end of the first comparison operation module, the output end of the first voltage detection module is connected to the input end of the first switch control module, and the output end of the first switch control module is connected to the VDD input end of the management and control chip;

[0008] The input end of the second voltage detection module is connected to the input signal, the output end of the second voltage detection module is connected to the input end of the second comparison operation module, the output end of the second voltage detection module is connected to the input end of the second switch control module, and the output end of the second switch control module is connected to the VDD input end of the management and control chip;

[0009] The first voltage detection module is used to detect the input voltage and output a first detection signal;

[0010] The first comparison operation module is used to perform a comparison operation on the first detection signal and a first reference signal, and output a first comparison signal according to the comparison result;

[0011] The first switch control module is used to control the power supply on and off of the management and control chip according to the first comparison signal;

[0012] The second voltage detection module is used to detect the input voltage and output a second detection signal;

[0013] The second comparison operation module is used to perform a comparison operation on the second detection signal and a second reference signal, and output a second comparison signal according to the comparison result;

[0014] The second switch control module is used to control the power supply on and off of the management and control chip according to the second comparison signal.

[0015] In the input voltage protection circuit of the control chip VDD described in the utility model, the first comparison operation module includes: a first current limiting unit, a first filtering unit, a first reference signal generating unit and a first comparison unit;

[0016] The input end of the first current limiting unit is connected to the output end of the first voltage detection module, the output end of the first current limiting unit is connected to the positive input end of the first comparison unit, the input end of the first filtering unit is connected to the output end of the first voltage detection module, the output end of the first filtering unit is grounded, the negative input end of the first comparison unit is connected to the first reference signal generating unit, and the output end of the first comparison unit is connected to the input end of the first switch control module.

[0017] In the input voltage protection circuit of the control chip VDD described in the utility model, the first current limiting unit includes: a sixth resistor; the first filtering unit includes: a sixth capacitor; the first reference signal generating unit includes: a fourth capacitor, a fifth resistor and a first reference device; the first comparing unit includes: a first comparator, a third diode, a fourth resistor, a fourth capacitor and a fifth capacitor;

[0018] The first end of the sixth resistor is connected to the output end of the first voltage detection module, the second end of the sixth resistor is connected to the positive input end of the first comparator, the first end of the sixth capacitor is connected to the output end of the first voltage detection module, and the second end of the sixth capacitor is grounded; the anode of the third diode is connected to the output end of the first comparator, the cathode of the third diode is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the positive input end of the first comparator, the negative input end of the first comparator is grounded through the fifth capacitor, the negative input end of the first comparator is also connected to the second end of the first reference, and the output end of the first comparator is connected to the input end of the first switch control module; the second end of the first reference is grounded through the fifth resistor and the fourth capacitor in sequence, the third end of the first reference is grounded, and the first end of the first reference is connected to its second end.

[0019] In the input voltage protection circuit of the control chip VDD described in the utility model, the first switch control module includes: a first switch unit and a second switch unit;

[0020] The input end of the first switch unit is connected to the output end of the first comparison operation module, the output end of the first switch unit is connected to the input end of the second switch unit, and the output end of the second switch unit is connected to the VDD input end of the control chip.

[0021] In the input voltage protection circuit of the control chip VDD described in the utility model, the first switch unit includes: a second switch tube, a third switch tube, a fourteenth resistor and a thirteenth resistor; the second switch unit includes: an eleventh resistor, a twelfth resistor, a second voltage regulator tube, a seventh capacitor and a fourth switch tube;

[0022] The first end of the second switch tube is connected to the output end of the first comparison operation module, the second end of the second switch tube is grounded, the third end of the second switch tube is connected to the first end of the third switch tube and the second end of the fourteenth resistor, the first end of the fourteenth resistor is connected to VCC, the first end of the third switch tube is also grounded through the thirteenth resistor, the third end of the third switch tube is connected to the first end of the fourth switch tube, and the second end of the third switch tube is grounded;

[0023] The first end of the fourth switch tube is also grounded through the twelfth resistor, the second end of the fourth switch tube is connected to the VDD input end of the control chip, the third end of the fourth switch tube is connected to VCC, the eleventh resistor is connected between the first end and the third end of the fourth switch tube, the cathode of the second voltage regulator tube is connected to the first end of the fourth switch tube, the anode of the second voltage regulator tube is grounded, the first end of the seventh capacitor is connected to the VDD input end of the control chip, and the second end of the seventh capacitor is grounded.

[0024] In the input voltage protection circuit of the control chip VDD described in the utility model, the second comparison operation module includes: a second current limiting unit, a second filtering unit, a second reference signal generating unit and a second comparison unit;

[0025] The input end of the second current limiting unit is connected to the output end of the second voltage detection module, the output end of the second current limiting unit is connected to the positive input end of the second comparison unit, the input end of the second filtering unit is connected to the output end of the second voltage detection module, the output end of the second filtering unit is grounded, the negative input end of the second comparison unit is connected to the second reference signal generating unit, and the output end of the second comparison unit is connected to the input end of the second switch control module.

[0026] In the input voltage protection circuit of the control chip VDD described in the utility model, the second current limiting unit includes: a nineteenth resistor; the second filtering unit includes: an eighth capacitor; the second reference signal generating unit includes: a second capacitor, an eighteenth resistor and a second reference device; the second comparing unit includes: a second comparator, a fourth diode, a seventeenth resistor, a second capacitor and a third capacitor;

[0027] The first end of the nineteenth resistor is connected to the output end of the second voltage detection module, the second end of the nineteenth resistor is connected to the positive input end of the second comparator, the first end of the eighth capacitor is connected to the output end of the second voltage detection module, and the second end of the eighth capacitor is grounded; the anode of the fourth diode is connected to the output end of the second comparator, the cathode of the fourth diode is connected to the first end of the seventeenth resistor, the second end of the seventeenth resistor is connected to the positive input end of the second comparator, the negative input end of the second comparator is grounded through the third capacitor, the negative input end of the second comparator is also connected to the second end of the second reference device, and the output end of the second comparator is connected to the input end of the second switch control module; the second end of the second reference device is grounded through the eighteenth resistor and the second capacitor in sequence, the third end of the second reference device is grounded, and the first end of the second reference device is connected to its second end.

[0028] In the input voltage protection circuit of the control chip VDD described in the utility model, the second switch control module includes: a third switch unit and a fourth switch unit;

[0029] The input end of the third switch unit is connected to the output end of the second comparison operation module, the output end of the third switch unit is connected to the input end of the fourth switch unit, and the output end of the fourth switch unit is connected to the VDD input end of the control chip.

[0030] In the input voltage protection circuit of the control chip VDD described in the utility model, the third switch unit includes: a fifth switch tube and a twenty-first resistor; the fourth switch unit includes: a first resistor, a twenty-second resistor, a third voltage regulator tube, a first capacitor and a first switch tube;

[0031] The first end of the fifth switch tube is connected to the output end of the second comparison operation module, the first end of the fifth switch tube is also grounded through the twenty-first resistor, the second end of the fifth switch tube is grounded, the third end of the fifth switch tube is connected to the first end of the first switch tube and the first end of the twenty-second resistor, the second end of the twenty-second resistor is connected to VCC, the first end of the first switch tube is also grounded through the first resistor, the third end of the first switch tube is connected to the second end of the twenty-second resistor and VCC, and the second end of the first switch tube is connected to the VDD input end of the control chip; the cathode of the third voltage regulator tube is connected to the first end of the first switch tube, the anode of the third voltage regulator tube is grounded, the first end of the first capacitor is connected to the VDD input end of the control chip, and the second end of the first capacitor is grounded.

[0032] The utility model also provides a driving power supply, including: the input voltage protection circuit of the control chip VDD mentioned above.

[0033] The input voltage protection circuit and driving power supply of the control chip VDD of the utility model have the following beneficial effects: including: input undervoltage protection circuit and input overvoltage protection circuit; the input undervoltage protection circuit includes: a first voltage detection module, a first comparison operation module and a first switch control module; the input overvoltage protection circuit includes: a second voltage detection module, a second comparison operation module and a second switch control module. The utility model detects the input voltage through the first voltage detection module and the second voltage detection module and compares it with the first reference signal and the second reference signal respectively using the first comparison operation module and the second comparison operation module, and then controls the power supply of the control chip by the first switch control module and the second switch control module respectively, so as to make the control chip not work when the input is undervoltage, so as to achieve the purpose of input undervoltage protection; and make the control chip not work when the input is overvoltage, so as to achieve the purpose of input overvoltage protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0035] Figure 1 This is a principle block diagram of the input voltage protection circuit of the control chip VDD provided by the utility model;

[0036] Figure 2 It is a circuit diagram of an input undervoltage protection circuit provided by the utility model;

[0037] Figure 3 The utility model provides a circuit diagram of an input overvoltage protection circuit. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0039] Figure 1 A principle block diagram of a preferred embodiment of an input voltage protection circuit for a control chip VDD provided by the utility model is shown.

[0040] Specifically, Figure 1 As shown, the input voltage protection circuit of the control chip VDD includes: an input undervoltage protection circuit and an input overvoltage protection circuit.

[0041] The input undervoltage protection circuit includes: a first voltage detection module 11 , a first comparison operation module 12 and a first switch control module 13 ; the input overvoltage protection circuit includes: a second voltage detection module 21 , a second comparison operation module 22 and a second switch control module 23 .

[0042] The input end of the first voltage detection module 11 is connected to the AC input end, the output end of the first voltage detection module 11 is connected to the input end of the first comparison operation module 12, the output end of the first voltage detection module 11 is connected to the input end of the first switch control module 13, and the output end of the first switch control module 13 is connected to the VDD input end of the management and control chip; the input end of the second voltage detection module 21 is connected to the input signal, the output end of the second voltage detection module 21 is connected to the input end of the second comparison operation module 22, the output end of the second voltage detection module 21 is connected to the input end of the second switch control module 23, and the output end of the second switch control module 23 is connected to the VDD input end of the management and control chip.

[0043] Specifically, the first voltage detection module 11 is used to detect the input voltage and output a first detection signal; the first comparison operation module 12 is used to compare the first detection signal with the first reference signal, and output a first comparison signal according to the comparison result; the first switch control module 13 is used to control the power supply of the management and control chip according to the first comparison signal.

[0044] In the embodiment of the utility model, by setting the first voltage detection module 11, the input voltage can be detected in real time, and the first detection signal is output based on the input voltage, and the first comparison operation module 12 compares the first detection signal with the first reference signal to output the first comparison signal according to the comparison result, and finally the first switch control module 13 controls the power supply on and off of the control chip according to the first comparison signal. Specifically, when the voltage value of the first detection signal is higher than the voltage value of the first reference signal, the first comparison signal is high level, at this time, the VDD input terminal of the control chip is normally powered; when the voltage value of the first detection signal is lower than the voltage value of the first reference signal, the first comparison signal is low level, at this time, it means that the input voltage is undervoltage state, and the first switch control module 13 shuts off the VDD input terminal of the control chip according to the low level, so that the control chip does not work, thereby achieving the purpose of input undervoltage protection.

[0045] Specifically, the second voltage detection module 21 is used to detect the input voltage and output a second detection signal; the second comparison operation module 22 is used to compare the second detection signal with the second reference signal, and output a second comparison signal according to the comparison result; the second switch control module 23 is used to control the power supply of the management and control chip according to the second comparison signal.

[0046] In the embodiment of the utility model, by setting the second voltage detection module 21, the input voltage can be detected in real time, and the second detection signal is output based on the input voltage. The second comparison operation module 22 compares the second detection signal with the second reference signal to output the second comparison signal according to the comparison result, and finally the second switch control module 23 controls the power supply on and off of the control chip according to the second comparison signal. Specifically, when the voltage value of the second detection signal is lower than the voltage value of the second reference signal, the second comparison signal is low level, at this time, the VDD input terminal of the control chip is normally powered; when the voltage value of the second detection signal is higher than the voltage value of the second reference signal, the second comparison signal is high level, at this time, it means that the input voltage is in an overvoltage state, and the second switch control module 23 turns off the VDD input terminal of the control chip according to the high level, so that the control chip does not work, thereby achieving the purpose of input overvoltage protection.

[0047] The utility model can realize undervoltage and overvoltage detection and protection control of the input voltage by adopting the above-mentioned simple hardware circuit structure. It can not only realize undervoltage and overvoltage protection of the input voltage in a simple structure and low-cost manner, but also can shut down the control chip when the input voltage is undervoltage or overvoltage, so as to achieve the purpose of controlling the control chip to stop working, thereby avoiding the problem of damage to the driving power supply due to undervoltage or overvoltage of the input voltage.

[0048] In a preferred embodiment, the first comparison operation module 12 includes: a first current limiting unit 121 , a first filtering unit 122 , a first reference signal generating unit 123 and a first comparing unit 124 .

[0049] The input end of the first current limiting unit 121 is connected to the output end of the first voltage detection module 11, the output end of the first current limiting unit 121 is connected to the positive input end of the first comparison unit 124, the input end of the first filtering unit 122 is connected to the output end of the first voltage detection module 11, the output end of the first filtering unit 122 is grounded, the negative input end of the first comparison unit 124 is connected to the first reference signal generating unit 123, and the output end of the first comparison unit 124 is connected to the input end of the first switch control module 13.

[0050] Among them, the first current limiting unit 121 is used to limit the current of the first detection signal output by the first voltage detection module 11, so as to transmit the first detection signal to the first comparison unit 124. The first filtering unit 122 is used to filter the first detection signal to reduce the ripple of the first detection signal and improve the reliability and stability of the first detection signal. The first reference signal generating unit 123 is used to generate a first reference signal to provide a reference for comparison reference to the first comparison unit 124. The first comparison unit 124 is used to compare the voltage value of the first detection signal with the voltage value of the first reference signal, and then output a first comparison signal according to the comparison result of the first detection signal and the first reference signal.

[0051] The first switch control module 13 includes: a first switch unit 131 and a second switch unit 132; the input end of the first switch unit 131 is connected to the output end of the first comparison operation module 12, the output end of the first switch unit 131 is connected to the input end of the second switch unit 132, and the output end of the second switch unit 132 is connected to the VDD input end of the control chip.

[0052] The first switch unit 131 is used to control the on / off of the second switch unit 132 , and the second switch unit 132 is used to control the on / off of the power supply of the VDD input terminal of the control chip.

[0053] In a preferred embodiment, the second comparison operation module 22 includes: a second current limiting unit 221 , a second filtering unit 222 , a second reference signal generating unit 223 and a second comparing unit 224 .

[0054] The input end of the second current limiting unit 221 is connected to the output end of the second voltage detection module 21, the output end of the second current limiting unit 221 is connected to the positive input end of the second comparison unit 224, the input end of the second filtering unit 222 is connected to the output end of the second voltage detection module 21, the output end of the second filtering unit 222 is grounded, the negative input end of the second comparison unit 224 is connected to the second reference signal generating unit 223, and the output end of the second comparison unit 224 is connected to the input end of the second switch control module 23.

[0055] Among them, the second current limiting unit 221 is used to limit the current of the second detection signal output by the second voltage detection module 21, so as to transmit the second detection signal to the second comparison unit 224. The second filtering unit 222 is used to filter the second detection signal to reduce the ripple of the second detection signal and improve the reliability and stability of the second detection signal. The second reference signal generating unit 223 is used to generate a second reference signal to provide a reference for comparison reference to the second comparison unit 224. The second comparison unit 224 is used to compare the voltage value of the second detection signal with the voltage value of the second reference signal, and then output a second comparison signal according to the comparison result of the second detection signal and the second reference signal.

[0056] The second switch control module 23 includes: a third switch unit 231 and a fourth switch unit 232; the input end of the third switch unit 231 is connected to the output end of the second comparison operation module 22, the output end of the third switch unit 231 is connected to the input end of the fourth switch unit 232, and the output end of the fourth switch unit 232 is connected to the VDD input end of the control chip.

[0057] The third switch unit 231 is used to control the on / off of the fourth switch unit 232 , and the fourth switch unit 232 is used to control the on / off of the power supply of the VDD input terminal of the control chip.

[0058] The input undervoltage protection circuit and the input overvoltage protection circuit of the utility model are described below with a specific embodiment.

[0059] refer to Figure 2 , Figure 2 A circuit diagram of a preferred embodiment of an input undervoltage protection circuit provided by the utility model.

[0060] In this embodiment, the first voltage detection module 11 includes: a first rectifying unit 111 and a first voltage dividing unit 112. The input end of the first rectifying unit 111 is connected to the AC input end, the output end of the first rectifying unit 111 is connected to the input end of the first voltage dividing unit 112, and the output end of the first voltage dividing unit 112 is connected to the input end of the first comparison operation module 12.

[0061] Specifically, Figure 2 As shown, the first rectifying unit 111 includes: a first rectifying diode D1 and a second rectifying diode D2; the first voltage dividing unit 112 includes: a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a tenth resistor R10.

[0062] The anode of the first rectifier diode D1 is connected to the neutral terminal (N terminal) of the AC input terminal, the anode of the second rectifier diode D2 is connected to the live terminal (L terminal) of the AC input terminal, the cathode of the first rectifier diode D1 and the cathode of the second rectifier diode D2 are grounded through the tenth resistor R10, the ninth resistor R9, the eighth resistor R8 and the seventh resistor R7 in sequence, and the connection end of the eighth resistor R8 and the seventh resistor R7 is connected to the input end of the first comparison operation module 12 as the output end of the first voltage detection module 11. Among them, L and N are the AC before the rectifier bridge.

[0063] Furthermore, if Figure 2 As shown, in this embodiment, the input undervoltage protection circuit further includes: a first voltage regulator ZD1; the first voltage regulator ZD1 is arranged in parallel with the seventh resistor R7. By arranging the first voltage regulator ZD1, the clamping effect on the first detection signal can be achieved to prevent the voltage value of the first detection signal from being too high and damaging the components of the first comparison operation module 12.

[0064] Specifically, Figure 2 As shown, the first current limiting unit 121 includes: a sixth resistor R6; the first filtering unit 122 includes: a sixth capacitor C6; the first reference signal generating unit 123 includes: a fourth capacitor C4, a fifth resistor R5 and a first reference device U2; the first comparing unit 124 includes: a first comparator U1-A, a third diode D3, a fourth resistor R4, a fourth capacitor C4 and a fifth capacitor C5.

[0065] The first end of the sixth resistor R6 is connected to the output end of the first voltage detection module 11 (i.e., the connection end of the eighth resistor R8 and the seventh resistor R7), the second end of the sixth resistor R6 is connected to the positive input end of the first comparator U1-A, the first end of the sixth capacitor C6 is connected to the output end of the first voltage detection module 11, and the second end of the sixth capacitor C6 is grounded; the anode of the third diode D3 is connected to the output end of the first comparator U1-A, the cathode of the third diode D3 is connected to the first end of the fourth resistor R4, the second end of the fourth resistor R4 is connected to the positive input end of the first comparator U1-A, the negative input end of the first comparator U1-A is grounded through the fifth capacitor C5, the negative input end of the first comparator U1-A is also connected to the second end of the first reference device U2, and the output end of the first comparator U1-A is connected to the input end of the first switch control module 13; the second end of the first reference device U2 is grounded through the fifth resistor R5 and the fourth capacitor C4 in sequence, the third end of the first reference device U2 is grounded, and the first end of the first reference device U2 is connected to its second end.

[0066] The first switch unit 131 includes: a second switch tube Q2, a third switch tube Q3, a fourteenth resistor R14 and a thirteenth resistor R13; the second switch unit 132 includes: an eleventh resistor R11, a twelfth resistor R12, a second voltage regulator tube DZ2, a seventh capacitor C7 and a fourth switch tube Q4.

[0067] The first end of the second switch tube Q2 is connected to the output end of the first comparison operation module 12, the second end of the second switch tube Q2 is grounded, the third end of the second switch tube Q2 is connected to the first end of the third switch tube Q3 and the second end of the fourteenth resistor R14, the first end of the fourteenth resistor R14 is connected to VCC, the first end of the third switch tube Q3 is also grounded through the thirteenth resistor R13, the third end of the third switch tube Q3 is connected to the first end of the fourth switch tube Q4, and the second end of the third switch tube Q3 is grounded. Among them, the first end of the second switch tube Q2 is the input end of the first switch unit 131.

[0068] The first end of the fourth switch tube Q4 is also grounded through the twelfth resistor R12, the second end of the fourth switch tube Q4 is connected to the VDD input end of the control chip, the third end of the fourth switch tube Q4 is connected to VCC, the eleventh resistor R11 is connected between the first end and the third end of the fourth switch tube Q4, the cathode of the second voltage regulator tube DZ2 is connected to the first end of the fourth switch tube Q4, the anode of the second voltage regulator tube DZ2 is grounded, the first end of the seventh capacitor C7 is connected to the VDD input end of the control chip, and the second end of the seventh capacitor C7 is grounded.

[0069] like Figure 2As shown, VCC is the auxiliary source power supply voltage, the first comparator U1-A can use a 358 comparator, and the first reference device U2 can use a TL431. Among them, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 can be NPN tubes or N-MOS tubes.

[0070] like Figure 2 As shown, after the input voltage is rectified by the first rectifier diode D1 and the second rectifier diode D2, it is divided by the tenth resistor R10 / the eighth resistor R8 / the ninth resistor R9 and the seventh resistor R7, and the obtained divided voltage signal is the first detection signal, that is, Figure 2 When the input voltage is lower than the set voltage, the voltage at point A is lower than the voltage of the first reference signal (generally set to 2.5V), and the QV connected to the second switch tube Q2 is at a low level (that is, the first comparator U1-A outputs a low level). At this time, the second switch tube Q2 is turned on, so that point C becomes a high level, the third switch tube Q3 is turned on, and the level of point D is pulled down, that is, point D is a low level, and the fourth switch tube Q4 is turned off, so that IC-VDD becomes a low level, the power supply of the VDD input terminal of the control chip is turned off, and the control chip does not work, thereby achieving the purpose of input undervoltage protection.

[0071] refer to Figure 3 , Figure 3 A circuit diagram of a preferred embodiment of an input overvoltage protection circuit provided by the utility model.

[0072] In this embodiment, specifically, Figure 3 As shown, the second voltage detection module 21 includes: a second voltage dividing unit, and the second voltage dividing unit includes: a second resistor R2, a fourteenth resistor R14, a fifteenth resistor R15 and a twentieth resistor R20.

[0073] like Figure 3 As shown, the first end of the second resistor R2 is connected to the input signal (HV), the second end of the second resistor R2 is grounded through the fourteenth resistor R14, the fifteenth resistor R15 and the twentieth resistor R20 in sequence, and the connection end of the fifteenth resistor R15 and the twentieth resistor R20 is connected to the input end of the second comparison operation module 22 as the output end of the second voltage detection module 21. Among them, HV is the voltage output after the rectifier bridge.

[0074] Furthermore, if Figure 3 As shown, in this embodiment, the input overvoltage protection circuit further includes: a fourth voltage regulator ZD4; the fourth voltage regulator ZD4 is arranged in parallel with the twentieth resistor R20. By arranging the fourth voltage regulator ZD4, the clamping effect on the second detection signal can be achieved to prevent the voltage value of the second detection signal from being too high and damaging the components of the second comparison operation module 22.

[0075] Specifically, Figure 3 As shown, the second current limiting unit 221 includes: a nineteenth resistor R19; the second filtering unit 222 includes: an eighth capacitor C8; the second reference signal generating unit 223 includes: a second capacitor C2, an eighteenth resistor R18 and a second reference device U4; the second comparing unit 224 includes: a second comparator U1-B, a fourth diode D4, a seventeenth resistor R17, a second capacitor C2 and a third capacitor C3.

[0076] The first end of the nineteenth resistor R19 is connected to the output end of the second voltage detection module 21 (the connection end of the fifteenth resistor R15 and the twentieth resistor R20), the second end of the nineteenth resistor R19 is connected to the positive input end of the second comparator U1-B, the first end of the eighth capacitor C8 is connected to the output end of the second voltage detection module 21, and the second end of the eighth capacitor C8 is grounded; the anode of the fourth diode D4 is connected to the output end of the second comparator U1-B, the cathode of the fourth diode D4 is connected to the first end of the seventeenth resistor R17, the second end of the seventeenth resistor R17 is connected to the positive input end of the second comparator U1-B, the negative input end of the second comparator U1-B is grounded through the third capacitor C3, the negative input end of the second comparator U1-B is also connected to the second end of the second reference device U4, and the output end of the second comparator U1-B is connected to the input end of the second switch control module 23; the second end of the second reference device U4 is grounded through the eighteenth resistor R18 and the second capacitor C2 in sequence, the third end of the second reference device U4 is grounded, and the first end of the second reference device U4 is connected to its second end.

[0077] like Figure 3 As shown, the third switch unit 231 includes: a fifth switch tube Q5 and a twenty-first resistor R21; the fourth switch unit 232 includes: a first resistor R1, a twenty-second resistor R22, a third voltage regulator tube ZD3, a first capacitor C1 and a first switch tube Q1.

[0078] A first end of the fifth switch tube Q5 is connected to the output end of the second comparison operation module 22, and the first end of the fifth switch tube Q5 is also grounded through the twenty-first resistor R21, and the second end of the fifth switch tube Q5 is grounded, and the third end of the fifth switch tube Q5 is connected to the first end of the first switch tube Q1 and the first end of the twenty-second resistor R22, and the second end of the twenty-second resistor R22 is connected to VCC, and the first end of the first switch tube Q1 is also grounded through the first resistor R1, and the third end of the first switch tube Q1 is connected to the second end of the twenty-second resistor R22 and VCC, and the second end of the first switch tube Q1 is connected to the VDD input end of the control chip; the cathode of the third voltage regulator tube ZD3 is connected to the first end of the first switch tube Q1, and the anode of the third voltage regulator tube ZD3 is grounded, the first end of the first capacitor C1 is connected to the VDD input end of the control chip, and the second end of the first capacitor C1 is grounded.

[0079] like Figure 3As shown, VCC is the auxiliary source power supply voltage, the first comparator U1-A can be a 358 comparator, and the first reference device U2 can be a TL431. The first switch tube Q1 and the fifth switch tube Q5 can be NPN tubes or N-MOS tubes.

[0080] like Figure 3 As shown, the input signal HV is divided by the second resistor R2 / the fourteenth resistor R14 / the fifteenth resistor R15 and the twentieth resistor R20, and the obtained divided voltage signal is the second detection signal, that is, Figure 3 When the input voltage is higher than the set voltage, the voltage at point A is higher than the voltage of the second reference signal (generally set to 2.5V), and the QV connected to the fifth switch tube Q5 is high (that is, the second comparator U1-B outputs a high level). At this time, the fifth switch tube Q5 is turned on, so that point D becomes a low level, the first switch tube Q1 is turned off, so that IC-VDD becomes a low level, the VDD input power supply of the control chip is turned off, and the control chip does not work, thereby achieving the purpose of input overvoltage protection.

[0081] It should be noted that, in this embodiment, Figure 2 and Figure 3 The first comparator U1-A and the second comparator U1-B may be packaged in the same component, or may be independently provided.

[0082] The utility model also provides a driving power supply, wherein the driving power supply comprises: an input voltage protection circuit of the control chip VDD disclosed in the embodiment of the utility model. Optionally, the driving power supply may include but is not limited to an LED driving power supply, an industrial driving power supply, etc.

[0083] The utility model can control the control chip to not work when the input is undervoltage or overvoltage by adjusting the input voltage protection circuit of the control chip VDD, so as to remind the customer that the voltage is too high or too low during use, thereby avoiding power supply damage.

[0084] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with the technology to understand the content of the utility model and implement it accordingly, and they cannot limit the protection scope of the utility model. All equivalent changes and modifications made to the scope of the claims of the utility model should fall within the scope of the claims of the utility model.

Claims

1. An input voltage protection circuit for controlling chip VDD, characterized in that: include: Input undervoltage protection circuit and input overvoltage protection circuit; The input undervoltage protection circuit includes: a first voltage detection module, a first comparison operation module and a first switch control module; the input overvoltage protection circuit includes: a second voltage detection module, a second comparison operation module and a second switch control module; The input end of the first voltage detection module is connected to the AC input end, the output end of the first voltage detection module is connected to the input end of the first comparison operation module, the output end of the first voltage detection module is connected to the input end of the first switch control module, and the output end of the first switch control module is connected to the VDD input end of the management and control chip; The input end of the second voltage detection module is connected to the input signal, the output end of the second voltage detection module is connected to the input end of the second comparison operation module, the output end of the second voltage detection module is connected to the input end of the second switch control module, and the output end of the second switch control module is connected to the VDD input end of the management and control chip; The first voltage detection module is used to detect the input voltage and output a first detection signal; The first comparison operation module is used to perform a comparison operation on the first detection signal and a first reference signal, and output a first comparison signal according to the comparison result; The first switch control module is used to control the power supply on and off of the management and control chip according to the first comparison signal; The second voltage detection module is used to detect the input voltage and output a second detection signal; The second comparison operation module is used to perform a comparison operation on the second detection signal and a second reference signal, and output a second comparison signal according to the comparison result; The second switch control module is used to control the power supply on and off of the management and control chip according to the second comparison signal.

2. The input voltage protection circuit of the control chip VDD according to claim 1, characterized in that: The first comparison operation module includes: a first current limiting unit, a first filtering unit, a first reference signal generating unit and a first comparison unit; The input end of the first current limiting unit is connected to the output end of the first voltage detection module, the output end of the first current limiting unit is connected to the positive input end of the first comparison unit, the input end of the first filtering unit is connected to the output end of the first voltage detection module, the output end of the first filtering unit is grounded, the negative input end of the first comparison unit is connected to the first reference signal generating unit, and the output end of the first comparison unit is connected to the input end of the first switch control module.

3. The input voltage protection circuit of the control chip VDD according to claim 2, characterized in that: The first current limiting unit includes: a sixth resistor; the first filtering unit includes: a sixth capacitor; the first reference signal generating unit includes: a fourth capacitor, a fifth resistor and a first reference device; the first comparing unit includes: a first comparator, a third diode, a fourth resistor, a fourth capacitor and a fifth capacitor; The first end of the sixth resistor is connected to the output end of the first voltage detection module, the second end of the sixth resistor is connected to the positive input end of the first comparator, the first end of the sixth capacitor is connected to the output end of the first voltage detection module, and the second end of the sixth capacitor is grounded; the anode of the third diode is connected to the output end of the first comparator, the cathode of the third diode is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the positive input end of the first comparator, the negative input end of the first comparator is grounded through the fifth capacitor, the negative input end of the first comparator is also connected to the second end of the first reference, and the output end of the first comparator is connected to the input end of the first switch control module; the second end of the first reference is grounded through the fifth resistor and the fourth capacitor in sequence, the third end of the first reference is grounded, and the first end of the first reference is connected to its second end.

4. The input voltage protection circuit of the control chip VDD according to claim 1, characterized in that: The first switch control module includes: a first switch unit and a second switch unit; The input end of the first switch unit is connected to the output end of the first comparison operation module, the output end of the first switch unit is connected to the input end of the second switch unit, and the output end of the second switch unit is connected to the VDD input end of the control chip.

5. The input voltage protection circuit of the control chip VDD according to claim 4, characterized in that: The first switch unit includes: a second switch tube, a third switch tube, a fourteenth resistor and a thirteenth resistor; the second switch unit includes: an eleventh resistor, a twelfth resistor, a second voltage regulator tube, a seventh capacitor and a fourth switch tube; The first end of the second switch tube is connected to the output end of the first comparison operation module, the second end of the second switch tube is grounded, the third end of the second switch tube is connected to the first end of the third switch tube and the second end of the fourteenth resistor, the first end of the fourteenth resistor is connected to VCC, the first end of the third switch tube is also grounded through the thirteenth resistor, the third end of the third switch tube is connected to the first end of the fourth switch tube, and the second end of the third switch tube is grounded; The first end of the fourth switch tube is also grounded through the twelfth resistor, the second end of the fourth switch tube is connected to the VDD input end of the control chip, the third end of the fourth switch tube is connected to VCC, the eleventh resistor is connected between the first end and the third end of the fourth switch tube, the cathode of the second voltage regulator tube is connected to the first end of the fourth switch tube, the anode of the second voltage regulator tube is grounded, the first end of the seventh capacitor is connected to the VDD input end of the control chip, and the second end of the seventh capacitor is grounded.

6. The input voltage protection circuit of the control chip VDD according to claim 1, characterized in that: The second comparison operation module includes: a second current limiting unit, a second filtering unit, a second reference signal generating unit and a second comparison unit; The input end of the second current limiting unit is connected to the output end of the second voltage detection module, the output end of the second current limiting unit is connected to the positive input end of the second comparison unit, the input end of the second filtering unit is connected to the output end of the second voltage detection module, the output end of the second filtering unit is grounded, the negative input end of the second comparison unit is connected to the second reference signal generating unit, and the output end of the second comparison unit is connected to the input end of the second switch control module.

7. The input voltage protection circuit of the control chip VDD according to claim 6, characterized in that: The second current limiting unit includes: a nineteenth resistor; the second filtering unit includes: an eighth capacitor; the second reference signal generating unit includes: a second capacitor, an eighteenth resistor and a second reference device; the second comparing unit includes: a second comparator, a fourth diode, a seventeenth resistor, a second capacitor and a third capacitor; The first end of the nineteenth resistor is connected to the output end of the second voltage detection module, the second end of the nineteenth resistor is connected to the positive input end of the second comparator, the first end of the eighth capacitor is connected to the output end of the second voltage detection module, and the second end of the eighth capacitor is grounded; the anode of the fourth diode is connected to the output end of the second comparator, the cathode of the fourth diode is connected to the first end of the seventeenth resistor, the second end of the seventeenth resistor is connected to the positive input end of the second comparator, the negative input end of the second comparator is grounded through the third capacitor, the negative input end of the second comparator is also connected to the second end of the second reference device, and the output end of the second comparator is connected to the input end of the second switch control module; the second end of the second reference device is grounded through the eighteenth resistor and the second capacitor in sequence, the third end of the second reference device is grounded, and the first end of the second reference device is connected to its second end.

8. The input voltage protection circuit of the control chip VDD according to claim 1, characterized in that: The second switch control module includes: a third switch unit and a fourth switch unit; The input end of the third switch unit is connected to the output end of the second comparison operation module, the output end of the third switch unit is connected to the input end of the fourth switch unit, and the output end of the fourth switch unit is connected to the VDD input end of the control chip.

9. The input voltage protection circuit of the control chip VDD according to claim 8, characterized in that: The third switch unit includes: a fifth switch tube and a twenty-first resistor; the fourth switch unit includes: a first resistor, a twenty-second resistor, a third voltage regulator tube, a first capacitor and a first switch tube; The first end of the fifth switch tube is connected to the output end of the second comparison operation module, the first end of the fifth switch tube is also grounded through the twenty-first resistor, the second end of the fifth switch tube is grounded, the third end of the fifth switch tube is connected to the first end of the first switch tube and the first end of the twenty-second resistor, the second end of the twenty-second resistor is connected to VCC, the first end of the first switch tube is also grounded through the first resistor, the third end of the first switch tube is connected to the second end of the twenty-second resistor and VCC, and the second end of the first switch tube is connected to the VDD input end of the control chip; the cathode of the third voltage regulator tube is connected to the first end of the first switch tube, the anode of the third voltage regulator tube is grounded, the first end of the first capacitor is connected to the VDD input end of the control chip, and the second end of the first capacitor is grounded.

10. A driving power supply, characterized in that: include: The input voltage protection circuit of the control chip VDD as described in any one of claims 1 to 9.

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