公开(公告)号：JPH10304652A

公开(公告)日：1998-11-13

申请号：JP35363997

申请日：1997-12-22

Applicant: ST MICROELECTRON INC

Inventor： HOPKINS THOMAS L

IPC: H02M3/00 ,  H03K5/13 ,  H03K7/08

Abstract: PROBLEM TO BE SOLVED: To provide an improved synchronous circuit for switching regulator by generating programmable pulse modulation output, so as to be synchronized in frequency and have duty cycle and phase shift which are selectable by a user and whose output is independent. SOLUTION: A circuit 11 involves four output modules 21a to 21d for respective pulse width modulation output. The respective output modules 21a to 21d generate the pulse width modulation outputs PWM1 to PWM4 which can conduct programming, so that it is high or low based on the values held by respective comparison registers 31, 39. Therefore, each of the output modules 21a to 21d can be programmed so as to generate independent pulse width modulation outputs PWM1 to PWM4 synchronized with the frequency of 4-bit counter 17 by duty cycle and phase shift which are selectable independently. In this case, the output module 21a is structurally identical to the output modules 21b to 21c in its structure.