Power integrated circuit with current protection, and overcurrent protection circuit and overcurrent protection method of same

Abstract

The invention discloses a power integrated circuit with current protection and an overcurrent protection circuit and an overcurrent method of the same. The power integrated circuit receives an input voltage and converts the input voltage into an output voltage to be provided for a load, wherein an output current is provided for the load by controlling a power transistor which is controlled by an output control unit. Further, a fixed current limiting critical value and a foldback current limiting critical value are designed in an overcurrent protection circuit for further controlling the power transistor. When the output current is larger than the fixed current limiting critical value, the output current is strangulated to a fixed current value so as to reduce the output voltage to a rated value; and when the output current is larger than the foldback current limiting critical value, the output current is limited to a low current value, so that the output voltage is reduced to a zero potential. Therefore, an inner circuit of the power integrated circuit and the load of an output end are protected.

Description

technical field [0001] The invention relates to a power integrated circuit and its overcurrent protection circuit and method, in particular to a power integrated circuit with a two-stage current limiting protection mechanism and its overcurrent protection circuit and method. Background technique [0002] In recent years, due to the development of science and technology, the output of electronic products has increased greatly. In electronic products, in addition to the functional circuit of the product itself, the most important part is the part of the power circuit, which is the so-called voltage. Regulators, voltage regulators and other power integrated circuits (PowerICs) of the same nature, these are enough to affect the stability of product operation. [0003] In terms of the above-mentioned voltage regulator, the voltage regulator is a circuit that can provide a fixed voltage to the load. According to the change of the load impedance, the output current of the voltage r...

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Problems solved by technology

[0006] However, the overcurrent protection circuit 9 of this design has two disadvantages: first, since the output current will flow through the sense resistor R 1 , so when the output current is large, it will cause the sense resistor R 1 The voltage across the sense resistor R is too large, resulting in 1 There is a large power loss on the

[0009] However, the disadvantages of this overcurrent protection circuit 9' are: first, there is no foldback current mechanism, and high heat loss will occur when the output terminal is short-circuited

That is to say, in addition to wasting power, when the voltage difference between input and output is large, the power transistor M 1 damage may occur

The second is that compensation capacitors need to be designed and used on the circuit, which will increase the area of ​​the power integrated circuit

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