TI中文支持网PMP40182在BUCK和BOOST转换时，TL594是如何切换PWM信号的，原理图上未看明白，请指教！
Johnsin Tao：
Hi应该和J2的Vsn/Vsp有关，感觉这一块电路图中不完整。
user4824708：
回复 Johnsin Tao:
是的，需要专业人士来解答一下！
Yuan Tan63：
Buck Mode:
Q3 is main FET and Q4 is the freewheel FET. the PWM duty cycle(Q3 turn on time )is increasing as output current increases.
Boost Mode:
Q4 is main FET and Q3 is the freewheel FET. the PWM duty cycle(Q4 turn on time )is increasing as output current increases.
Yuan Tan63：
Buck Mode:
Q3 is main FET and Q4 is the freewheel FET. the PWM duty cycle(Q3 turn on time )is increasing as output current increases.
Boost Mode:
Q4 is main FET and Q3 is the freewheel FET. the PWM duty cycle(Q4 turn on time )is increasing as output current increases.
Buck Mode:
Q3 is main FET and Q4 is the freewheel FET. the PWM duty cycle(Q3 turn on time )is increasing as output current increases.
Boost Mode:
Q4 is main FET and Q3 is the freewheel FET. the PWM duty cycle(Q4 turn on time )is increasing as output current increases.
