Patent ID: 6023741
Filing Date: 2000-02-08
Classification: G06F,H03K

Abstract:
A pulse width modulation (PWM) control circuit comprising:a free run counter for counting a pulse signal to generate a counted value, and for generating an overflow signal when said counted value is equal to a predetermined value;a slave compare register for storing a set value;a master compare register for storing said set value;a transfer control circuit having a transfer permission mode for allowing said set value to be transferred from said master compare register to said slave compare register in response to the overflow signal, and for preventing a new set value from being entered into the master compare register, and a transfer inhibition mode for inhibiting the transfer of said set value from the master compare register to the slave compare register in response to said overflow signal and for allowing a new set value to be entered into the master compare register;a comparing circuit for comparing said counted value in said free run counter and said set value transferred into said slave compare register and for generating a coincident signal when said counted value is coincident with said set value; andan output circuit for generating a PWM signal in response to said overflow signal and said coincident signal.