AM4964

Document number: DS37241 Rev. 2 - 2

1 of 21

www.diodes.com

June 2014

© Diodes Incorporated

AM4964

A Product Line of

Diodes Incorporated

SINGLE PHASE FULL WAVE DIRECT PWM MOTOR DRIVER

Description

The AM4964 is highly integrated feature rich single phase Brushless

Direct Current (BLDC) full wave motor driver with combined PWM and

temperature speed control function for fans, blowers and extractors.

For system flexibility, the motor speed can be controlled by an

external PWM signal and temperature sensed by Thermal resister at

the same time. Based on external input PWM and temperature

signals, the AM4964 adjusts the output PWM duty cycle. If the input

PWM duty is constant, the output PWM duty varies with temperature

sensed by Thermal resister sensor between the low and high

temperature corners. If the temperature signal is constant, the output

duty varies with the external input PWM duty. The low and high

temperature corners and the output PWM duty gap between these

temperature corners are adjustable

To help protect the motor coil, the AM4964 provides a rotor lock

protection which shuts down the output if rotor lock is detected. The

device automatically re-starts when the rotor lock is removed.

AM4964

provides

a

tachometer

Frequency

Generator

(FG). The FG output is the magnetic change frequency.

The AM4964 is available in TSSOP-20EP package.

Features



Flexible Speed Control Options



Combined PWM+Thermistor Speed Control



PWM Speed Control



DC Voltage Speed Control



Adjustable Low and High Temperature Corners



Full Speed When Thermal Resistor is Shorted



Adjustable

Output

Duty

Gap

between

High

and

Low

Temperature when 100% PWM Input



Built-in oscillator

– No external capacitor



Built-in Minimal Speed Setup Circuit



Alpha Slope Adjustable



Rotation Speed Indicator (FG)



Built-in Temperature Control Circuit



Built-in Thermal Shutdown Circuit



Lock Protection and Auto-restart



Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2)



Halogen and Antimony Free.

“Green” Device (Note 3)

Pin Assignments

(Top View)

NC

PGND

OUT2

VCC

VMIN

PWM

CF

FG

RT

TL

IN+

HB

IN-

RADJ

CT

SGND

TH

TA

OUT1

NC

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

TSSOP-20EP

Applications



CPU Cooler Fan in PC



Brushless DC Motor Driver

Notes:

1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.

2. See http://www.diodes.com/quality/lead_free.html

for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"

and Lead-free.

3. Halogen- and Antimony-

free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and

<1000ppm antimony compounds.