Title:
PULSE WIDTH MODULATION CONTROLLER
Document Type and Number:
Japanese Patent JPH03201005
Kind Code:
A
Abstract:
PURPOSE:To easily obtain a system with high reliability by providing a means which limits both up and down operations of an up-down counter and a means which stops the pulse width control actions. CONSTITUTION:When the output value of an up-down counter 2 is reduced less than a 1st prescribed level, the output of a counter limiter I 1-b is set at '1' and a signal is inputted to the counter 2 so that it is always kept in an up-counting state. When the output value of the counter 2 is more than a 2nd prescribed level set by a data latch 6 and less than a 3rd prescribed level, the output of a counter limiter II 1-c is set at '1' and the up-down counting actions of the counter 2 are stopped. When the output value of the counter 2 exceeds the 3rd prescribed level higher than the maximum level, the output of a maximum value comparator 1-a is set at '1'. Thus the counter 2 is controlled so that it always performs a down-counting action. In such a constitution, a system having high reliability is easily obtained.
Inventors:
KITAHARA SATOHIKO
Application Number:
JP33837589A
Publication Date:
September 02, 1991
Filing Date:
December 28, 1989
Export Citation:
Assignee:
CANON KK
International Classes:
G03G21/00; G03G15/00; G05B11/26; (IPC1-7): G03G15/00; G05B11/26
Attorney, Agent or Firm:
Hiroyuki Niwa (1 outside)