Browse Prior Art Database

Four Channel Pulse Width Modulation Generator with I2C Interface

IP.com Disclosure Number: IPCOM000014791D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2003-Jun-20
Document File: 6 page(s) / 93K

Publishing Venue

IBM

Abstract

4 Channel Pulse Width Modulation Generator

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 64% of the total text.

Page 1 of 6

Four Channel Pulse Width Modulation Generator with I2C Interface

       4 Channel Pulse Width Modulation Generator
2with IC Interface Proposal Version 0.00

1

Page 2 of 6

1 Introduction

This document describes an integrated circuit for generating multiple independent PWM waveforms for fan control circuits. A 2low pin count, and IC interface allows addition of this circuit to applications with minimal cost.

Date Revision Description 10/12/99 0.00 Proposal Initial proposal for Integrated circuit.

2

Page 3 of 6

2 Overview

This document present design guidelines
for the implementation of a four-channel
pulse width modulation circuit. Low pin
count, allows simple placement into
applications. Configuration is done via
I2C access. This provides a simple
interface to a microcontroller.
Functionality is adequate for controlling
fan speed circuits.

This document does not address electrical
concerns.

3 Pin definitions

Low pin count design allows simple placement to applications. All logic for generating PWM waveforms is provided in this circuit.

Signal Name Description SCL I2C Clock SDA I2C Data A0 I2C Address Select A1 I2C Address Select (optional) A2 I2C Address Select (optional) MCLK Master Clock In
PWM 0 PWM output channel 0 PWM 1 PWM output channel 1 PWM 2 PWM output channel 2 PWM 3 PWM output channel 3
Vdd Power

3

Page 4 of 6

Vss Ground

4

Page 5 of 6

4 I2C interface

One byte write cycles are used to set individual PWM duty cycles. To set the clock prescaler, a two byte write sequence is...