Accurate scan-mode voltage detection circuit
First Claim
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1. A voltage detection circuit comprising:
- first and second transistors, gates of the first and second transistors coupled to each other, sources of the first and second transistors coupled to each other, the gate of the first transistor coupled to a drain of the first transistor;
a first switch circuit configured for selectively coupling a positive voltage to the sources of the first and second transistors;
first and second bipolar transistors, bases of the first and second bipolar transistors coupled to each other, a collector of the first bipolar transistor coupled to the drain of the first transistor, a collector of the second bipolar transistor coupled to a drain of the second transistor;
a pair of resistors coupled in series between an emitter of the first bipolar transistor and a negative power, an emitter of the second bipolar transistor coupled to an intermediate node between the pair of resistors, wherein the base of the first bipolar transistor is regarded as a detection voltage input, and the collector of the second bipolar transistor is regarded as a detection result output.
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Abstract
A scan mode is used in a voltage detection circuit. An oscillator in the circuit is always on and a system including the voltage detection circuit detects various abnormal conditions, such as overcharging, overdischarging and overcurrent one by one for some clocks. To reduce the power consumption, the voltage detection circuit is turned on only once for several clocks. The on-time is very short and lasts about only one tenth of a clock cycle time. In other times, the voltage detection circuit is turned off to save power consumption.
37 Citations
13 Claims
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1. A voltage detection circuit comprising:
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first and second transistors, gates of the first and second transistors coupled to each other, sources of the first and second transistors coupled to each other, the gate of the first transistor coupled to a drain of the first transistor; a first switch circuit configured for selectively coupling a positive voltage to the sources of the first and second transistors; first and second bipolar transistors, bases of the first and second bipolar transistors coupled to each other, a collector of the first bipolar transistor coupled to the drain of the first transistor, a collector of the second bipolar transistor coupled to a drain of the second transistor; a pair of resistors coupled in series between an emitter of the first bipolar transistor and a negative power, an emitter of the second bipolar transistor coupled to an intermediate node between the pair of resistors, wherein the base of the first bipolar transistor is regarded as a detection voltage input, and the collector of the second bipolar transistor is regarded as a detection result output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A voltage detection circuit comprising:
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a voltage divider coupled between a positive terminal and a negative terminal of a battery and configured for dividing a battery voltage and providing a divided voltage of the battery voltage; a voltage comparator coupled between the positive terminal and the negative terminal of the battery and configured for comparing the divided voltage from the voltage divider with a reference voltage formed therein and outputting a comparative result; an output control circuit coupled between the positive terminal and the negative terminal of the battery and configured for amplifying and shaping the comparative result to form a voltage detection result; and an enable circuit configured for receiving an enable signal to switch on current paths from the positive terminal to the negative terminal of the battery of the voltage divider, the voltage comparator and the output control circuit, or receiving a disenable signal to switch off current paths from the positive terminal to the negative terminal of the battery of the voltage divider, the voltage comparator and the output control circuit, wherein the voltage comparator and the output control circuit comprises plural MOS transistors therein, and voltages on gates of the MOS transistors are maintained to be substantially near to normal operation voltages after the current paths from the positive terminal to the negative terminal of the battery of the voltage divider, the voltage comparator and the output control circuit are switched off. - View Dependent Claims (10, 11, 12, 13)
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Specification