Title:
PULSE WIDTH MODULATING DEVICE
Document Type and Number:
Japanese Patent JP3284317
Kind Code:
B2
Abstract:
PURPOSE: To easily set the duty ratio from 0% to 100%.
CONSTITUTION: A pulse width modulating device 30 consists of a counting circuit 32 which outputs an overflow signal at the tinge of return from the final value to the initial value, a comparing circuit 34 provided with a comparator 35 which compares a counted value N from the counting circuit with a duty value (m) stored in a register 36 and outputs a coincidence signal at the time of coincidence between them and a zero detector 38 which outputs the coincidence signal at the time of detecting that the duty value in the register is 0, and a pulse width modulation signal output circuit 42 which inverts the value of a binary output pulse signal in response to the overflow signal and the coincidence signal to output the pulse width modulation signal which has the duty ratio corresponding to the duty value, and a preset device 46 is provided which writes a preliminarily designated value in the counting circuit and forces the counting circuit to count the value from the designated value to the final value. When 100% duty ratio is written, the output pulse does not drop to '0' in the last part.
Inventors:
Great lord
Keisuke Ninomiya
Keisuke Ninomiya
Application Number:
JP10028392A
Publication Date:
May 20, 2002
Filing Date:
March 27, 1992
Export Citation:
Assignee:
Motorola, Inc.
International Classes:
H03K7/08; (IPC1-7): H03K7/08
Attorney, Agent or Firm:
Shinsuke Onuki (1 person outside)