Datasheet

TMC262 DATASHEET (Rev. 2.14 / 2016-JUL-14) 46
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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.
+V12
+V
M
VHS
5VOUT
470nF
VS
GND
SRA
D
ENABLE
TMC262
CSN
D
SCK
SDI
D
D
SDO
D
R
SENSE
DIE PAD
20mΩ for 14A peak
(resp. 7A peak)
Provide sufficient filtering capacity
near bridge transistors (electrolyt
capacitors and ceramic capacitors)
S
D
G
N
N
motor coil A
HA2
HA1
BMA1
BMA2
S
D
G
N
N
LA1
LA2
100n
16V
100n
SRB
HB2
HB1
BMB1
BMB2
LB1
LB2
STEP
D
DIR
D
CLK
D
SG_TST
D
8-20MHz
VCC_IO
D
D
TEST_SE
3.3V or 5V
+V
CC
100n
12V gate
supply
step & dir
(optional)
SPI
stallGuard
output
TEST_ANA
22R
HIP4082
(Intersil)
High current NMOS
FET switches
S
D
G
S
D
G
+V12
Second bridge identical
ALI
BLI
AHI
BHI
BHO
AHO
BHS
AHS
ALO
BLO
10µF
DLY
R
DLY
+V12
10µF
AHBBHB
Full bridge
gate driver IC
up to 80V
10k
VDD
VSS
DIS
Attention: High side capacitors would
discharge at 100% duty cycle within a
few seconds. Disable driver if open
load occurs in stand still.
+V12
2R2
2R2
2R2
2R2
100µF
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.