TMC239_1 Datasheet, PDF (10/29 Pages) TRINAMIC Motion Control GmbH & Co. KG. – High current microstep stepper motor driver with protection, diagnostics and SPI Interface

TMC239 / TMC239A DATA SHEET (V2.11 / 2009-Jul-30)
10
Using additional Power Drivers
For higher voltage and higher output current it is possible to add external MOSFET gate drivers. Both,
dedicated transistor drivers are suitable, as well as a circuit based on standard HCMOS drivers. It is
important to understand the function of dedicated gate drivers for N-channel transistors: Since the
chopping also can be stopped in open load conditions, the gate drive circuit for the upper transistors
should allow for continuous ON conditions. In the schematic below this is satisfied by attaching a weak
additional charge pump oscillator and pumping the VS up to the high voltage supply. Do not enable the
TMC239, before the gate driver capacitors are charged to an appropriate voltage. A current sensing
comparator in the VM line pulling down the VT pin by some 100mV on overcurrent can be added, if
required. Since the TMC239 in this application can not sense switch-off of the transistor gates to
ensure break-before-make operation, the break before-make-delays have to be set by capacitive
loading of its transistor drive outputs. The capacitors CdHS and CdLS are charged / discharged with
the nominal gate current. The opposite output is not enabled, before the switching-off output has been
discharged to 0.5V. To calculate the timing, refer to the required logic levels of the attached power
driver, resp. the attached PMOS. For CdHS and CdLS 470pF give about 100ns. Both circuits do not
show decoupling capacitors and further details.
+12V
VS
VT
HA1
C_DHS
470p
to other
bridges
C-Pump
20kHz
ICM7555
22K
2n2
TMC249/
TMC239
small signal P-
MOS, e.g. BSS84
LA1
C_DLS
470p
SRA
4.7nF
opt.
100R
HS-Driver
LS-
Driver
IR2101
SLP
10K
Set HS and LS
current to 10mA
1µF
12V
390R
390R
+V_M e.g. 50V
High current, high
voltage MOS, e.g.
SI4450
NN
Coil
NN
R_S
+V_S 7..15V
VS
1K
120R
1/2 74HC244
VCC
VT
on high side
TMC249/
TMC239
1K
C_DHS
HA1
55V low current
N-MOS
ADJ 390R
LM337
HV
IN
OUT
LA1
1K
C_DLS
/OE
VM-5.2V
1/2 74HC244
on low side
/OE
SRA
100R
GND
+5V
VCC
100R
GND
SLP
15K
set to 7 mA high-
side drive current
+V_M 20..60V
High voltage logic
level MOS bridge
PP
Coil
NN
R_S
Copyright © 2005, TRINAMIC Motion Control GmbH & Co KG