1 Features
• Predriver for Single-Phase Full-Wave Drive
– PNP-NMOS is Used as an External Power TR,
Enabling High-Efficiency Low-Consumption
Drive by Means of the Low-Saturation Output
and Single-Phase Full-Wave Drive (PMOS-
NMOS Also Applicable)
• External PWM Input Enabling Variable Speed
Control
– Separately-Excited Upper Direct PWM (f = 25
kHz) Control Method, Enabling Highly Silent
Speed Control
• Compatible with 12-V, 24-V, and 48-V Power
Supplies
• Current Limiter Circuit Incorporated
– Chopper Type Current Limit at Start
• Reactive Current Cut Circuit Incorporated
– Reactive Current Before Phase Change is Cut
to Enable Silent and Low-Consumption Drive
• Minimum Speed Setting Pin
– Minimum Speed Can Be Set With External
Resistor. Start Assistance Circuit Enables Start
at Extremely Low Speed.
• Constant-Voltage Output Pin for Hall Bias
• Lock Protection and Automatic Reset Functions
Incorporated
• FG (Rotation Speed Detection) and RD (Lock
Detection) Output

2 Applications
• Server Fans (Up to 48 V)
• Appliance Fans (Up to 48 V)

3 Description
The TMP814 is a single-phase bipolar variable speed
fan motor predriver that works with an external PWM
signal. A highly efficient, quiet and low-power
consumption motor driver circuit, with a large variable speed, can be implemented by adding a small
number of external components.
This device is optimal for driving large scale fan
motors (with large air volume and large current) such
as those used in servers and consumer products.