TMC603 DATA SHEET (V. 1.06 / 26. Mar. 2009)
13
PWM1
BH1
BL1
OUT1
PWM1
OUT2
Microcontroller
with BLDC PWM
unit
TMC603
TMC603
Block (Hall or hallFX) or
sine commutated BLDC
motor
PWM1
OUT
BH1
BL1
Sine commutated BLDC
motor
Microcontroller with
3 PWM outputs
INV_BL
+VCC
BBM_EN
PWM1
OUT
DIG
BH1
BL1
Microcontroller
with 3 PWM
outputs
TMC603
TMC603
Block (Hall) commutated
BLDC motor
OUT
PWM1
OUT
DIG OUT /
HI-Z
BH1
2k2
BL1
Block (Hall) or sine
commutated BLDC
motor
Microcontroller with
3 PWM outputs
INV_BL
+VCC
BBM_EN
DIG OUT
DIG OUT
BH1
BL1
TMC603
PWM1
OUT
2k2
ENABLE
Block (hallFX)
commutated BLDC
motor
Microcontroller
with 1 PWM output
DIG IN
/ERR_OUT
BBM_EN
+VCC
figure 7: examples for microcontroller PWM control
5.2.4 Slope control
The TMC603 driver stage provides a constant current output stage slope control. This allows to adapt
driver strength to the drive requirements of the power MOSFET and to adjust the output slope by
providing for a controlled gate charge and discharge. A slower slope causes less electromagnetic
emission, but at the same time power dissipation of the power transistors rises. The duration of the
complete switching event depends on the total gate charge. The voltage transition of the output takes
place during the so called miller plateau (see figure 6). The miller plateau results from the gate to drain
capacity of the MOSFET charging / discharging during the switching. From the datasheet of the
transistor (see example in figure 8) it can be seen, that the miller plateau typically covers only a part
(e.g. one quarter) of the complete charging event. The gate voltage level, where the miller plateau
starts, depends on the gate threshold voltage of the transistor and on the actual load current.
MOSFET gate charge vs. switching event
10
8
25
VM
20
15
10
5
6
4
2
0
0
0
5
10
15
20
25
QMILLER
QG – Total gate charge (nC)
figure 8: MOSFET gate charge as available in device data sheet vs. switching event
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TRINAMIC [ TRINAMIC MOTION CONTROL GMBH & CO. KG. ]
