TMC603 DATA SHEET (V. 1.06 / 26. Mar. 2009)
11
A zener diode at the gate (range 12V to 15V) protects the high-side MOSFET in case of a short to
GND event: Should the bridge be shorted, the gate driver output is forced to stay at a maximum of the
zener voltage above the source of the transistor. Further it prevents the gate voltage from dropping
below source level.
The maximum permissible MOSFET driver current depends on the motor supply voltage:
Parameter
Symbol
Max
Unit
MOSFET driver current with VVM < 30V
MOSFET driver current with 30V < VVM < 50V
MOSFET driver current with VVM = 50V
IHSX, ILSX
150
mA
150-2.5*(VVM-30V) mA
100 mA
IHSX, ILSX
Pin
Comments
LSx
HSx
BMx
Low side MOSFET driver output. The driver current is set by resistor RSLP
High side MOSFET driver output. The driver current is set by resistor RSLP
Bridge center used for current sensing and for control of the high side driver.
For unused bridges, connect BMx pin to GND and leave the driver outputs
unconnected. Place the external protection resistor near the IC pin.
RSLP
The resistor connected to this pin controls the MOSFET gate driver current. A 40µA
current out of this pin (resistor value of 100k to GND) results in the nominal
maximum current at full supply range. Keep interconnection between IC and resistor
short, to avoid stray capacitance to adjacent signal traces of modulating the set
current.
Resistor range: 60 k to 500 k
VLS
Low side driver supply voltage for driving low side gates
Charge pump supply voltage. Provides high side driver supply
Power GND for MOSFET drivers, connect directly to GND
VCP
GNDP
BHx
High side driver control signal: A positive level switches on the high side.
For unused bridges, tie to GND.
BLx
Low side driver control signal: Polarity can be reversed via INV_BL
INV_BL
Allows inversion of BLx input active level (low: BLx is active high).
When high, each BLx and BHx can be connected in parallel in order to use only 3
PWM outputs for bridge control. Be sure to switch on internal break-before-make logic
(BBM_EN = Vcc) to avoid bridge short circuits in this case.
5.2.2 Break-before-make logic
Each half-bridge has to be protected against cross conduction during switching events. When
switching off the low-side MOSFET, its gate first needs to be discharged, before the high side
MOSFET is allowed to be switched on. The same goes when switching off the high-side MOSFET and
switching on the low-side MOSFET. The time for charging and discharging of the MOSFET gates
depends on the MOSFET gate charge and the driver current set by RSLP. When the BBM logic is
enabled, the TMC603 measures the gate voltage and automatically delays switching on of the
opposite bridge transistor, until its counterpart is discharged. The BBM logic also prevents
unintentional bridge short circuits, in case both, LSx and HSx, become switched on. The first active
signal has priority.
Alternatively, the required time can be calculated and pre-compensated in the PWM block of the
microcontroller driving the TMC603 (external BBM control).
Copyright © 2008 TRINAMIC Motion Control GmbH & Co. KG
TRINAMIC [ TRINAMIC MOTION CONTROL GMBH & CO. KG. ]
