TMC603A Datasheet, PDF (29/44 Pages) TRINAMIC Motion Control GmbH & Co. KG. – Three phase motor driver with BLDC back EMF commutation hallFX™ and current sensing

TMC603A DATA SHEET (V. 1.15 / 2009-Nov-19)
29
5.5.5 Reverse polarity protection
Some applications need to be protected against a reversed biased power supply, i.e. for automotive
applications. A highly efficient reverse polarity protection based on an N channel MOSFET can simply
be added due to the availability of a charge pump voltage. This type of reverse polarity protection
allows feeding back energy into the supply, and thus is preferable to a pure diode reverse polarity
protection.
+Terminal
BC846
-Terminal
Reverse polarity power
10k
MOS (i.e. same type as
bridge transistors)
10k
+VM protected
(to bridge)
VM
VCP
figure 19: adding a reverse polarity protection
5.5.6 Standby with zero power consumption
In battery powered applications, a standby function often is desired. It allows switching the unit on or
off without the need for a mechanical high power switch. In principle, the bridge driver MOSFETs can
switch off the motor completely, but the TMC603 and its switching regulator still need to be switched
off in order to reduce current consumption to zero. Only a low energy standby power supply will
remain on, in order to wake up the system controller. This standby power supply can be generated by
a low current zener diode plus a resistor to the battery voltage, buffered by a capacitor. The example
in the schematic uses a P channel MOSFET to switch off power for the TMC603 and any additional
ICs which are directly supplied by the battery. Before entering standby mode, the motor shall be
stopped and the TMC603 should be disabled.
electronic
ON switch
enable
+Vbattery
+VM to bridge, only
100K
220n
POWER
FDC5614P _SWITCH
+VM switched,
3A max.
10µ
27k
VM
TMC603
ENABLE
HSx
(only shown for
one high side
MOSFET)
figure 20: low power standby
5.5.7 Low voltage operation down to 9V
In low voltage operation, it is important to keep the gate driving voltages as high as possible. The
switching regulator for VLS thus is not needed and can be left out. Tie the pin COSC to GND. VLS
becomes directly tied to +VM, which is possible as long as the supply voltage does not exceed 14V
(16V peak). However, now a source for the Villard voltage doubler is missing. A simple solution is to
use a CMOS 555 timer circuit (e.g. TLC555) oscillating at 250 kHz (square wave) to drive the voltage
doubler.
Copyright © 2009 TRINAMIC Motion Control GmbH & Co. KG