Laptop memory power supply circuit (0.9-1.8V)

Laptop memory power supply circuit (0.9-1.8V)

Shown is the memory power supply circuit of a notebook computer , which uses SC486 as the power management chip.     There are two sets of PWM signal generation circuits in the SC486 chip. One set outputs two PWM signals with opposite phases from the @ pin and the @ pin, which are added to the gates of the Ql and Q2 field effect transistors respectively, so that the two field effect transistors are turned on alternately. Convert the battery's supply voltage (9 V-19 V) into a pulse voltage, and then filter it through Ll, C13, and C14 to +1.8 V (10 A) to power the memory. At the same time, the +1,8 V power supply is added to the @ pin and @ pin of SC486. There is a second set of PWM signal generation circuits and two field effect transistors inside the chip. These two field effect transistors turn the 1.8 V voltage into a pulse signal, which is output by the ⑩ and @ pins of SC486. After filtering by C15 and C16, it outputs a 0.9 V DC voltage to power the circuit in the memory .