Three Phase Field Effect Transistor Pre-driver 34937A Industrial0 pages

Freescale Semiconductor
Technical Data

Document Number: MC34937
Rev. 3.0, 11/2015

Three Phase Field Effect Transistor
Pre-driver

34937A
Industrial

The 34937A is a field effect transistor (FET) pre-driver designed for three phase
motor control and similar applications. The integrated circuit (IC) uses
SMARTMOS technology.
The IC contains three high-side FET pre-drivers and three low-side FET predrivers. Three external bootstrap capacitors provide gate charge to the highside FETs.
The IC interfaces to a MCU via six direct input control signals, an SPI port for
device setup and asynchronous reset, enable, and interrupt signals. Both 5.0 V
and 3.0 V logic level inputs are accepted and 5.0 V logic level outputs are
provided.

THREE PHASE PRE-DRIVER

Features
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Extended supply voltage operating range: 6.0 V to 58 V
Gate drive capability of 1.0 A to 2.5 A
Wide dead time range (50 ns to 12 μs) programmable via the SPI port
Charge pump ensures sufficient external FET drive at low supply voltages
Device protection against reverse charge-injection from CGD and CGS of
external FETS
Integrated overcurrent, desaturation, and phase fault-detection
Immunity against positive or negative transient voltage spikes on the gate
driver
Current shoot-through protection built into dead time control
Supports direct 3.3 V and 5.0 V logic interface to MCUs
Integrated current sensing amplifier
Device configuration and diagnostics through the SPI

EK SUFFIX (Pb-FREE)
98ASA99334D
54-PIN SOICW-EP

Applications
• 12 V to 48 V 3-phase brushless DC (BLDC) motors
and permanent magnet synchronous motors (PMSM)
• E-Bike, hospital beds, electric chair/scooter
• CPAPs, inflation pumps, industrial fans
• Portable power tools, commercial fans/blowers
• Small kitchen appliances

VSYS

34937
VPUMP

VSUP

PUMP
VPWR
VLS
VDD
VSS
3
3
3

MCU
OR
DSP

PX_HS
PX_LS
PHASEX
CS
SI
SCLK
SO
RST
INT
EN1
EN2
GND

PA_HS_G
PB_HS_G
PC_HS_G

PA_HS_S
PB_HS_S
PC_HS_S

PA_LS_G
PB_LS_G
PC_LS_G
PX_LS_S
AMP_P
AMP_N
AMP_OUT

RSEN

Figure 1. 34937A Simplified Application Diagram

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