Pulse width modulation control equipment


Application Number: 00108755
Application Date: 2000.05.31
Publication Number: 1296329
Publication Date: 2001.05.23
Priority Information: 1999/6/1 EP 99401317.5
International: H02M1/00;H02M7/5395;H04N5/63
Applicant(s) Name: SEmiconductor Element Industries Inc.
Address:
Inventor(s) Name: Joseph Haramic;Fransova Lehemit;Juraier Turky
Patent Agency Code: 11038
Patent Agent: ma gao
Abstract A pulse Width Modulation (PWM) control circuit is used in a switched-mode power supply (SMPS) having a normal mode and a standby mode, for controlling and regulating the SMPS. An input of the PWM control circuit is arranged to receive a signal indicating an amount of current supplied by the supply. An over-current determining arrangement provides an over-current signal. A further input of the PWM control circuit receives a regulation signal. A logic circuit within the PWM control circuit compares the over-current signal and the regulation signal in order to determine whether the switched-mode power supply is in standby mode or normal mode, thus avoiding the need for a dedicated control pin to indicate standby and normal modes.