Over-voltage protection circuit of PWM regulator and method thereof

• Main Authors: FANG, LI-WEN, CHEN, AN-DONG, SU, HONG-DE
• Format: Patent
• Language: Chinese; English
• Published: 16.04.2010
• Subjects: CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS; GENERATION

An over-voltage protection circuit of PWM regulator and method thereof are disclosed. In which a voltage detector circuit is used to detect the supply voltage inputted into the power transistor of pulse width modulation (PWM) regulator, and when the voltage detector circuit detects the supply voltage reaching a predetermined voltage value, the voltage detector circuit outputs an over-voltage protection signal to turn off the driving on the power transistor by the PWM driving signal outputted from a control driving circuit. Because the breakdown voltage of the power transistor in the OFF state is 10% to 20% higher than that of the power transistor in the ON state, the power transistor of the PWM regulator can be protected from being damaged. Furthermore, because there is no need to connect switch to the input power in series or to connect voltage clamping device to the input power in parallel, the requirement of over-voltage protection function can be conveniently met without reducing the working efficiency of