Short circuit protection device

Abstract

The invention discloses a short circuit protection device and method. The short circuit protection device includes a current detection circuit to detect the output current of the output circuit and output a current detection signal when the output current is greater than the preset current; the control circuit receives the current detection signal and controls the output circuit to close; the voltage detection circuit detects the output voltage of the output circuit and When the output voltage is not in the preset voltage range, continue to detect the output voltage, and when it is detected that the output voltage is in the preset voltage range, output the voltage detection signal to the control circuit to control the output circuit, so as to reduce the power-on after the output circuit is short-circuited The number of restarts and repeated high-current shocks.

Description

technical field [0001] The invention relates to a protection device, in particular to a short circuit protection device. Background technique [0002] The output power of the audio power amplifier is high and the output current is large. When a large current flows through the output power tube for a long time, especially when the output short circuit occurs, it is easy to burn out the output power tube, so it needs to be protected against the output short circuit. In the process of use, the output of the power amplifier may be short-circuited with the power line, ground wire, and both ends of the load due to improper operation. Using a single short-circuit protection method will cause the power amplifier to be repeatedly powered on and restarted or subjected to repeated high-current shocks during short-circuit. reduce its life and reliability. The existing power amplifier short-circuit protection methods mainly include the following three types: 1) Self-locking short-circui...

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Problems solved by technology

[0003] However, the existing three methods have different shortcomings, such as the self-locking short-circuit protection method. After the output of the power amplifier is short-circuited, the power amplifier needs to be restarted to work normally. inconvenient

The circular short circuit protection method can avoid the situation of instantaneous short circuit shutting down the power amplifier caused by human misoperation. After the short circuit fault is eliminated, the power amplifier can resume normal work without restarting, but the output power tube of the power amplifier will always be in a cycle of overcurrent and protection State, adversely affect the life and reliability of the power amplifier

The blanking self-locking short-circuit protection can prevent the output power tube of the power amplifier from repeatedly being in the overcurrent state, but the protection behavior for different situations such as short-circuit between the power amplifier output and the power line, ground wire, and load is single, and the short-circuit caused by the short-circuit within the set judgment time The high current frequency needs to reach the set value before locking, and the power amplifier must be restarted to make it work normally. Not only the risk of high current impact is high, but also the operation is inconvenient

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