| 摘要 |
A power supply controller is disclosed that uses power MOSFET on-resistance Rds_on for over-temperature protection. The parameter, on-resistance Rds_on, functions as a temperature dependent variable that enables a pulse width modulation controller to turn OFF when the controller is overheated. The MOSFET on-resistance Rds_on of the pulse width modulation controller senses the temperature that is compared with a predetermined temperature threshold where the pulse width modulation controller detects an over-temperature condition when the sensed temperature exceeds the predetermined temperature threshold. A pulse width modulation controller for over-temperature protection comprises a Rp resistor having a first end and a second end; a voltage comparator circuit, the voltage comparator circuit having a first input, a second input, and an output, the first input of the voltage comparator circuit connected to the second end of the Rp resistor; and a MOSFET having an on-resistance Rds_on when the MOSFET is in an ON state, the Rds_on having a first end and a second end, the second end of the Rds_on connected to the second input of the voltage comparator circuit, the Rds_on sensing a temperature value and the value of the Rds_on fluctuating depending on the change in the temperature value.
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