Automatic-recovery-capable short circuit protection circuit for low dropout linear regulator

Abstract

The invention discloses an automatic-recovery-capable short circuit protection circuit for a low dropout linear regulator. The short circuit protection circuit mainly comprises a second transistor, a third transistor, a fourth transistor, a fifth transistor, a third resistor and a fourth resistor. The short circuit protection circuit is simple in structure and high in reliability, and the static power consumption of the circuit is reduced remarkably. As the short circuit protection circuit has an automatic recovery function, the output of the low dropout linear regulator can recover immediately after being divorced from a short circuit state.

Description

technical field [0001] The invention relates to a short-circuit protection circuit, in particular to a short-circuit protection circuit capable of automatic recovery for a low-dropout linear regulator. Background technique [0002] Low-dropout linear regulator (LDO) has the advantages of simple structure, low power consumption, low noise, small package and few peripheral components, etc. It has been widely used in consumer electronics products, such as smart phones, MP3, tablet computers, Digital cameras, Bluetooth headsets, etc. It can greatly reduce the saturation voltage of the output FET, so that the input voltage can be very close to the output voltage, and it reduces power consumption and greatly prolongs the battery life. [0003] However, as the power device of the system, the low-dropout linear regulator has always been a weak link in the reliability design of the system. For example, the output short circuit is a common abnormal operation mode of the low-dropout l...

AI Technical Summary

Problems solved by technology

However, the circuit protection based on the above circuit structure has the following disadvantages: 1. The circuit structure is relatively complicated, that is, a reference circuit is required to generate the reference voltage 103, and a comparator 105 is also required

2. When the low-dropout linear regulator is not in the short-circuit state, the short-circuit protection circuit is also consuming power, which cannot meet the low-power consumption requirements of the low-dropout linear regulator at light load or no load.

3. If the comparator 105 in the circuit does not have a latch function, when short-circuited, the output power transistor M1 will be in a repeated switching state, if the comparator 105 has a latch function, once short-circuited, the The output power tube M1 can be turned off, but if the output is out of the short-circuit state, the low-dropout linear regulator will restart only when the power is turned on again, so the short-circuit protection does not have an automatic recovery function

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