CN-224233332-U - Under-voltage protection circuit and driver

CN224233332UCN 224233332 UCN224233332 UCN 224233332UCN-224233332-U

Abstract

The utility model provides an undervoltage protection circuit and a driver. The under-voltage protection circuit comprises a sampling circuit and a comparison circuit. The input end of the sampling circuit is coupled with the power supply voltage end. The comparison circuit comprises a first power tube, a second power tube, a first current mirror circuit, a second current mirror circuit and a third current mirror circuit. The first power tube comprises a first end, a second end and a control end, and the control end of the first power tube is coupled with the sampling circuit. The control end of the second power tube is coupled with the control end of the first power tube. The first end of the first current mirror circuit is coupled to the first end of the first power tube. The first end of the second current mirror circuit is coupled to the second end of the first current mirror circuit. The first end of the third current mirror circuit is coupled to the first end of the second power tube, and the second end of the third current mirror circuit is coupled to the second end of the second current mirror circuit. The undervoltage protection circuit and the driver provided by the utility model have the advantages of simplifying the circuit structure, reducing the chip cost and having lower chip power consumption.

Inventors

LI ZHENGYANG
YE JUN
LIAO JIANPING

Assignees

厦门市必易微电子技术有限公司

Dates

Publication Date: 20260512
Application Date: 20250425

Claims (10)

1. The utility model provides an undervoltage protection circuit which characterized in that, undervoltage protection circuit includes sampling circuit and comparison circuit, and the input of sampling circuit couples the power supply voltage end, and sampling circuit is used for the sampling to obtain the sampling signal, comparison circuit includes: the first power tube comprises a first end, a second end and a control end, wherein the control end is coupled with the sampling circuit; the second power tube comprises a first end, a second end and a control end, and the control end of the second power tube is coupled with the control end of the first power tube; a first current mirror circuit, a first end of which is coupled with a first end of the first power tube; A second current mirror circuit having a first end coupled to the second end of the first current mirror circuit; The first end of the third current mirror circuit is coupled to the first end of the second power tube, and the second end of the third current mirror circuit is coupled to the second end of the second current mirror circuit.
2. The undervoltage protection circuit of claim 1, wherein the sampling circuit comprises a third resistor and a fourth resistor, a first terminal of the third resistor is coupled to the supply voltage terminal, a first terminal of the fourth resistor is coupled to a second terminal of the third resistor, and a second terminal of the fourth resistor is coupled to ground.
3. The undervoltage protection circuit of claim 2, wherein the sampling circuit further comprises a first capacitor, a first terminal of the first capacitor is coupled to a first terminal of the fourth resistor, and a second terminal of the first capacitor is coupled to ground.
4. The undervoltage protection circuit of claim 2, wherein the sampling circuit further comprises a fifth power tube and a fifth resistor, the fifth resistor is connected in series with the fourth resistor, a first end of the fifth resistor is coupled to a second end of the fourth resistor, a second end of the fifth resistor is coupled to ground, a first end of the fifth power tube is coupled to the first end of the fifth resistor, a second end of the fifth power tube is coupled to the second end of the fifth resistor, and a control end of the fifth power tube is coupled to an output end of the comparison circuit.
5. The undervoltage protection circuit of claim 1, wherein the comparison circuit further comprises a first resistor and a second resistor, a first end of the first resistor is coupled to the second end of the first power tube, a first end of the second resistor is coupled to the second end of the first resistor and the second end of the second power tube, respectively, and a second end of the second resistor is coupled to ground.
6. The undervoltage protection circuit of claim 1, further comprising a snubber circuit comprising a second capacitor and a first hysteresis comparator circuit, wherein a first end of the second capacitor is coupled to the second end of the second current mirror circuit, wherein a second end of the second capacitor is coupled to ground, and wherein an input of the first hysteresis comparator circuit is coupled to the first end of the second capacitor.
7. The undervoltage protection circuit of claim 6, wherein the buffer circuit further comprises a signal processing circuit, an input of the signal processing circuit is coupled to an output of the first hysteresis comparison circuit, and the signal processing circuit is configured to perform signal enhancement and/or signal shaping on an output signal of the first hysteresis comparison circuit.
8. The undervoltage protection circuit of claim 1, wherein the first power transistor and the second power transistor are both transistors.
9. The undervoltage protection circuit of claim 1, wherein the second current mirror circuit comprises a third power tube and a fourth power tube, a first end of the third power tube is coupled to the second end of the first current mirror circuit, a second end of the third power tube is coupled to ground, a first end of the fourth power tube is coupled to the second end of the third current mirror circuit, a second end of the fourth power tube is coupled to ground, and a control end of the fourth power tube is coupled to the control end of the third power tube.
10. A driver comprising a drive circuit and an under-voltage protection circuit as claimed in any one of claims 1-9, an input of the drive circuit being coupled to an output of the under-voltage protection circuit.

Description

Under-voltage protection circuit and driver Technical Field The utility model belongs to the field of power electronics, and relates to an undervoltage protection circuit and a driver. Background A variety of protection circuits are typically provided in the driver to ensure proper operation of the circuit. Common protection circuits include under-voltage protection circuits, over-temperature protection circuits, and the like. The undervoltage protection circuit monitors the power supply voltage in real time, outputs an undervoltage protection signal when the power supply voltage is lower than a safety threshold value, and avoids the chip from causing faults or damage due to low-voltage operation by cutting off the power supply or taking protection measures and other means. As shown in fig. 1, the driver includes a sampling circuit, a comparison circuit, and a driving circuit. The under-voltage protection circuit obtains sampling voltage through the sampling circuit, compares the reference voltage with the sampling voltage to generate a comparison signal, and the driving circuit controls the working state of the driver according to the comparison signal. The common undervoltage protection circuit needs a band-gap reference to provide a reference voltage, and the current source circuit provides bias current for the comparator to work, so that the circuit structure is complex, and the power consumption is higher. In view of the above, there is a need to provide a new structure for solving at least some of the above problems. Disclosure of utility model The present utility model is directed to an under-voltage protection circuit and driver that address one or more of the problems of the prior art. According to one aspect of the present utility model, an under-voltage protection circuit is disclosed, the under-voltage protection circuit includes a sampling circuit and a comparison circuit, an input terminal of the sampling circuit is coupled to a supply voltage terminal, the sampling circuit is used for sampling to obtain a sampling signal, and the comparison circuit includes: the first power tube comprises a first end, a second end and a control end, wherein the control end is coupled with the sampling circuit; the second power tube comprises a first end, a second end and a control end, and the control end of the second power tube is coupled with the control end of the first power tube; a first current mirror circuit, a first end of which is coupled with a first end of the first power tube; A second current mirror circuit having a first end coupled to the second end of the first current mirror circuit; The first end of the third current mirror circuit is coupled to the first end of the second power tube, and the second end of the third current mirror circuit is coupled to the second end of the second current mirror circuit. In one embodiment, the sampling circuit includes a third resistor and a fourth resistor, wherein a first end of the third resistor is coupled to the power supply voltage end, a first end of the fourth resistor is coupled to a second end of the third resistor, and a second end of the fourth resistor is coupled to ground. In one embodiment, the sampling circuit further includes a first capacitor, a first end of the first capacitor is coupled to a first end of the fourth resistor, and a second end of the first capacitor is coupled to ground. In one embodiment, the sampling circuit further comprises a fifth power tube and a fifth resistor, the fifth resistor is connected in series with the fourth resistor, a first end of the fifth resistor is coupled to a second end of the fourth resistor, a second end of the fifth resistor is coupled to ground, a first end of the fifth power tube is coupled to the first end of the fifth resistor, a second end of the fifth power tube is coupled to the second end of the fifth resistor, and a control end of the fifth power tube is coupled to an output end of the comparison circuit. In one embodiment, the comparing circuit further includes a first resistor and a second resistor, the first end of the first resistor is coupled to the second end of the first power tube, the first end of the second resistor is coupled to the second end of the first resistor and the second end of the second power tube, respectively, and the second end of the second resistor is coupled to ground. In one embodiment, the under-voltage protection circuit further comprises a buffer circuit, the buffer circuit comprises a second capacitor and a first hysteresis comparison circuit, a first end of the second capacitor is coupled to a second end of the second current mirror circuit, a second end of the second capacitor is coupled to ground, and an input end of the first hysteresis comparison circuit is coupled to the first end of the second capacitor. In one embodiment, the buffer circuit further includes a signal processing circuit, an input terminal of the signal processing circuit is coupled