TMC262 DATASHEET (Rev. 2.07 / 2013-FEB-14)
46
15 External Power Stage
The TMC262 uses a completely complementary driving scheme for the power MOSFETs. This allows
using the low-side gate driver outputs to control external gate drivers for the power MOSFETs. In this
case, the external gate driver must provide the break-before-make function. You can directly connect
gate driver chips like the TMC603 as gate drivers for high-current NMOS transistor bridges. The TMC603
also supplies a gate-drive voltage regulator and allows 100% duty cycle. See the TMC603 datasheet for
more information. The examples below show standard low-side and high-side drivers for boosting the
TMC262. The higher gate-driving capability allows designs that exceed 20A and voltages above 60V.
Two example schematics are shown for different gate-driver configurations.
12V gate
+V12
supply
100n
16V
Attention: High side capacitors would
discharge at 100% duty cycle within a
few seconds. Disable driver if open
load occurs in stand still.
100n
+V12
VHS
TMC262
VM
Provide sufficient filtering capacity
near bridge transistors (electrolyt
capacitors and ceramic capacitors)
5VOUT
+VCC
+VM up to 80V
VCC_IO
BHB
HIP4082
(Intersil)
AHB
D
D
470nF
10µF
10µF
3.3V or 5V
8-20MHz
100µF
BHO
100n
2R2
2R2
D
S
D
S
HA1
HA2
AHO
High current NMOS
FET switches
N
N
N
N
G
G
CLK
VDD
DIS
BHS
AHS
+V12
BMA1
BMA2
Full bridge
gate driver IC
BHI
AHI
BLI
ALI
motor coil A
STEP
DIR
D
D
step & dir
(optional)
D
S
D
S
LA2
LA1
ALO
BLO
G
G
2R2
2R2
TEST_SE
ENABLE
D
D
DLY
VSS
20mΩ for 14A peak
(resp. 7A peak)
RSENSE
SRA
SRB
22R
CSN
SCK
SDI
D
D
D
D
RDLY
10k
SPI
SDO
Second bridge identical
LB1
LB2
+V12
stallGuard
output
SG_TST
D
BMB2
BMB1
HB2
HB1
DIE PAD
GND
TEST_ANA
Figure 15.1 High-current, high-voltage power stage using external gate drivers (minimum part count)
The short to GND protection of the TMC262 cannot be used in the configuration shown in Figure 15.1.
The driver cannot be fully disabled, because the external gate driver just switches on either the high-
side MOSFET or the low-side MOSFET. In this configuration, the external driver adds break-before-make
capability. A configuration that takes advantage of the TMC262 short to GND protection is shown in
Figure 15.2. The control style shown in this example can also be applied to the gate driver shown in
Figure 15.1.
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