Principle Analysis of Inverter Driver Chip

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Principle Analysis of Inverter Driver Chip [Copy link]

The commonly used driver chip qcpl329 has tube voltage drop protection, that is, there is a signal to monitor the tube voltage drop at a set time. There is another driver chip that also has the tube voltage drop protection function, which seems to be hcpl3120.

The problem is that the first type with voltage drop protection will reset after a few dozen milliseconds (probably), but the second type will not reset after a period of time and will only reset after a complete power failure. What is the circuit principle of this function of these two chips? It seems to take away the memory?

maychang

[What is the circuit principle of this function of these two chips? It seems to take away the memory? ]

Take a look at the triggers (RS trigger, JK trigger, D trigger...) and monostable circuits in the textbook "Digital Circuits". The difference in this function of these two chips is the difference between triggers and monostable circuits.

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QCPL329, when it detects that the tube voltage drop is lower than the set threshold, it will automatically reset after tens of milliseconds. This design may be to prevent false triggering caused by short-term overload

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The protection mechanism of HCPL3120 will not reset automatically, or the reset time is long, and external intervention, such as power failure, is required to reset the protection state.

There is a situation where, for example, a true overload condition is detected and no damage is caused to other circuit components due to automatic reset.

The protection concepts of the two chips are different