ETC TMC239

TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
1
TMC 239 – DATA SHEET
High Current Microstep Stepper Motor Driver
with protection / diagnosis and SPI Interface
TRINAMIC
M I C R O C H I P S
®
TRINAMIC Microchips GmbH
Deelbögenkamp 4C
D – 22297 Hamburg
GERMANY
T +49 - (0) 40 - 51 48 06 - 0
F +49 - (0) 40 - 51 48 06 - 60
WWW.TRINAMIC.COM
[email protected]
Features
The TMC239 is a dual full bridge driver IC for stepper motor control applications. It is realized in a
HVCMOS technology and directly drives eight external Low-RDS-ON high efficiency MOSFETs. The
driver transistors can be chosen depending on output current or environment temperature. Its low
current consumption and high efficiency together with the miniature package make the TMC239 a
perfect solution for embedded motion control and for battery powered devices. It supports more than
3000mA coil current. With additional drivers, motor current and voltage can be increased. Internal
DACs allow microstepping as well as smart current control. The device can be controlled by a serial
i
interface (SPI™ ) or by analog / digital input signals. Short circuit, temperature and undervoltage
protection is integrated.
•
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•
•
•
•
•
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•
•
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•
•
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Control via SPI with easy-to-use 12 bit protocol or external analog / digital signals
Short circuit and over temperature protection integrated
Status flags for overcurrent, open load, over temperature, temperature pre-warning, undervoltage
Integrated 4 bit DACs allow up to 16 times microstepping via SPI, any resolution via analog control
Mixed decay feature for smooth motor operation
Slope control user programmable to reduce electromagnetic emissions
Chopper frequency programmable via a single capacitor or external clock
Current control allows cool motor and driver operation
Internal open load detector
7V to 30V motor supply voltage
More than 3000mA using 8 external MOS transistors
External drivers can be added for higher motor voltages and higher currents (e.g. 75V, 10A)
Only 4 external PMOS transistors required for unipolar operation
3.3V or 5V operation for digital part
Low power consumption via low RDS-ON power stage
Standby and shutdown mode available
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
Life support policy
TRINAMIC Microchips GmbH does not authorize
or warrant any of its products for use in life
support systems, without the specific written
consent of TRINAMIC Microchips GmbH.
Life support systems are equipment intended to
support or sustain life, and whose failure to
perform, when properly used in accordance with
instructions provided, can be reasonably
expected to result in personal injury or death.
© TRINAMIC Microchips GmbH 2002
Information given in this data sheet is believed to
be accurate and reliable. However no
responsibility is assumed for the consequences
of its use nor for any infringement of patents or
other rights of third parties, which may result form
its use.
Specifications subject to change without notice.
Copyright © 2002, TRINAMIC Microchips GmbH
2
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
3
Pinning
1
28
HA2
LA2
2
27
HA1
SRA
3
26
ANN
25
GNDA
24
SLP
OSC
4
SDO
5
SDI
6
SCK
7
TMC239 SO28
LA1
23
INA
22
INB
21
VCC
20
GND
CSN
8
ENN
9
SPE
10
19
VS
BL1
11
18
VT
SRB
12
17
BL2
LB2
13
16
HB1
LB1
14
15
HB2
Package codes
Package
Temperature range Code/marking
SO28
automotive *)
TMC239-SA
LPCC28 (6*6mm) automotive
TMC239-LA
to be announced
*) ICs with date code prior to 0104 are not yet tested according to automotive standards, but are usable
within the complete temperature range.
SO28 Dimensions
I
D
A
K
H
B
Copyright © 2002, TRINAMIC Microchips GmbH
E
F
G
C
REF
A
B
C
D
E
F
G
H
I
K
MIN.
10
17.7
7.4
MAX.
10.65
18.1
7.6
1.4
2.65
0.25
0.1
0.3
0.36
0.49
0.4
1.1
1.27
All dimensions are in mm.
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
4
Application Circuit / Block diagram
+VM
BL1
BL2
220nF
VS
TMC239
OSC
OSC
HA1
Current Controlled
Gate Drivers
PWM-CTRL
+VCC
Undervoltage
100nF
Temperature
HA2
P
N
SDI
[PHB]
SDO
Parallel
Control
[ERR]
CSN
N
LA1
RS
0
Control & Diagnosis
[PHA]
SPIInterface
SCK
P
Coil A
LA2
SRA
[MDBN]
RSH
VT
1nF
VCC
100µF
DAC
4
1
INA
REFSEL
VREF
DAC
INB
4
1
0
SRB
RS
PWM-CTRL
Current Controlled
Gate Drivers
LB1
REFSEL
SPE
ANN
ENN
AGND
GND
LB2
N
N
Coil B
HB2
P
P
HB1
SLP
[MDAN]
stand alone mode
RSLP
[...]: function in stand alone mode
Pin functions
Pin
Function
Pin
Function
VS
Motor supply voltage
VT
Short to GND detection comparator –
connect to VS if not used
VCC
3.0-5.5V supply voltage for analog
and logic circuits
GND
Power ground
AGND
Analog ground (Reference for SRA, OSC
SRB, OSC, SLP, INA, INB)
Oscillator capacitor or external clock
input for chopper
INA
Analog current control phase A
INB
Analog current control input phase B
SCK
Clock input of serial interface
SDI
Data input of serial interface
SDO
Data output of serial interface
CSN
Chip select input of serial interface
ENN
Device enable (low active), high
causes a total shutdown and resets
all registers
SPE
Enable SPI mode (high active). Tie to
GND for non-SPI applications
ANN
Enable analog current control (low
active): Enables INA and INB for
output current control
SLP
Slope control resistor. Tie to GND for
fastest slope
BL1, BL2
Digital blank time select
SRA, SRB
Bridge A/B current sense resistor input
LA1, LA2,
LB1, LB2
Outputs for low side N-channel
transistors
HA1, HA2, Outputs for high side P-channel
HB1, HB2 transistors
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
5
Selecting power transistors
Selection of power transistors for the TMC239 depends on required current, voltage and thermal
conditions. Driving transistors directly with the TMC239 is only limited by the gate capacity of these
transistors. If the total gate charge is too high, slope time increases and leads to a higher switching
power dissipation. Typical applications can reach a current in excess of 3A, while the maximum voltage
is limited to 30V. A total gate charge of below 10nC per transistor is recommended. The table below
shows a choice of transistors which can be driven directly by the TMC239. The maximum application
current mainly is a function of cooling and environment temperature. The given values are more
conservative. Peak currents typically can be higher by a factor of 1.5 for a limited time.
List of recommended transistors
Manufacturer
and type
Siliconix
SI 3552
Siliconix
SI 5504
ST Micro
STS2DNF30L
STS3DPF30L
IRF 5851
IRF 9952
IRF 7509
Fairchild Semi
FDS 8333C
Siliconix
SI 1901
Package
(#Trans)
TSOP6
(1N,1P)
1206-8
(1N,1P)
SO8
(2N)
(2P)
TSOP6
(1N,1P)
SO8
(1N,1P)
Micro8
(1N,1P)
SO8
(1N,1P)
SOT363-6
(2P)
Volts N-type
Volts P-type
30V
30V
30V
30V
RDSON
[Ohm]
0.105
0.200
0.085
0.165
Total gate
charge [nC]
2.5
3.0
5.0
5.5
30V
30V
20V
20V
30V
30V
30V
30V
30V
30V
30V
0.11
0.15
0.090
0.135
0.10
0.25
0.11
0.20
0.08
0.13
0.480
4.5
5.5
6.0
6.0
6.9
6.1
7.8
7.5
4.7
4.1
0.86
Typical maximum
application current
1500mA
2000mA
2000mA
1500mA
2500mA
2000mA
3000mA
200mA unipolar
Layout considerations
RSH
For optimal operation of the circuit a careful board layout is important, because of the combination of
high current chopper operation coupled with high accuracy threshold comparators. Please pay special
attention to massive grounding. Depending on the required motor current, either a single massive
ground plane or a ground plane plus star connection of the power traces may be used. The schematic
shows how the high current paths can be routed separately, so that the chopper current does not flow
through the system’s GND-plane. Tie the TMC239’s AGND and GND to the GND plane. Additionally,
use enough filtering capacitors located near to the board’s power supply input and small ceramic
capacitors near to the power supply connections of the TMC239. Use low inductance sense resistors,
or add a ceramic capacitor in parallel to each resistor to avoid high voltage spikes. In some
applications it may become necessary to introduce additional RC-filtering into the VT and SRA / SRB
line, as shown in the schematic, to prevent
spikes from triggering the short circuit
VS
optional filter
protection or the chopper comparator. If you
100nF
4.7nF
want to take advantage of the thermal
VT
protection and diagnosis, ensure, that the
100R
+VM
power transistors are very close to the
GND
package, and that there is a good thermal
TMC239
Bridge A
Bridge B
optional filter
contact between the TMC239 and the external
SRA
C
transistors. Please be aware, that long or thin
100R
SRB
GND traces to the sense resistors may add
R
R
100R
substantial resistance and thus reduce output
3.3 GND
10nF
current. The same is valid for the high side
AGND
GNDshunt resistor.
VM
SA
SB
Plane
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
6
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 senses switch-off of the transistor gates to ensure break-before-make
operation, the break before-make-delays can be increased 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. Both
circuits do not show decoupling capacitors and further details.
+15V
VS
to other
bridges
VT
C-Pump
20kHz
ICM7555
CDHS
HA1
TMC239
1K
+VM e.g. 75V
small signal PMOS, e.g. SI1901
High current, high
voltage MOS bridge
1µF
10nF
15V
N
HS-Driver
N
Coil
LA1
LSDriver
N
N
CDLS
IR2101
SRA
RS
100R
10nF
opt.
+VS 7..15V
+VM 20..60V
VS
1K
VCC
120R
High voltage logic
level MOS bridge
1/2 74HC244
on high side
VT
P
1K
CDHS
ADJ
HA1
LM337
HV
55V low current
N-MOS
390R
OUT
/OE
GND
VM-5.2V
IN
TMC239
P
100R
+5V
Coil
VCC
1/2 74HC244
on low side
LA1
N
1K
CDLS
N
100R
/OE
GND
SRA
RS
SLP
15K
set to 7 mA highside drive current
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
7
Serial interface word assignment
The SPI data word sets the current and polarity for both coils. By applying consecutive values,
describing a sine and a cosine wave, the motor can be driven in microsteps. Every microstep is
initiated by its own telegram. Please refer to the description of the analog mode for details on the
waveforms required.
Serial data word transmitted to TMC239
(MSB transmitted first)
Bit
Name
Function
Remark
11
MDA
mixed decay enable phase A
“1” = mixed decay
10
CA3
current bridge A.3
MSB
9
CA2
current bridge A.2
8
CA1
current bridge A.1
7
CA0
current bridge A.0
LSB
6
PHA
polarity bridge A
“0” = current flow from OA1 to OA2
5
MDB
mixed decay enable phase B
“1” = mixed decay
4
CB3
current bridge B.3
MSB
3
CB2
current bridge B.2
2
CB1
current bridge B.1
1
CB0
current bridge B.0
LSB
0
PHB
polarity bridge B
“0” = current flow from OB1 to OB2
Serial data word transmitted from TMC239
(MSB transmitted first)
Bit
Name
Function
Remark
11
0
always “0”
10
0
always “0”
9
0
always “0”
8
1
always “1”
7
OT
overtemperature
“1” = chip off due to overtemperature
6
OTPW
temperature prewarning
“1” = prewarning temperature exceeded
5
UV
driver undervoltage
“1” = undervoltage on VS
4
OCHS
overcurrent high side
3 PWM cycles with overcurrent within 63 PWM cycles
3
OLB
open load bridge B
no PWM switch off for 14 oscillator cycles
2
OLA
open load bridge A
no PWM switch off for 14 oscillator cycles
1
OCA
overcurrent bridge B low side
3 PWM cycles with overcurrent within 63 PWM cycles
0
OCB
overcurrent bridge A low side
3 PWM cycles with overcurrent within 63 PWM cycles
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
8
Typical winding current values
Current setting
Percentage of
current
Typical trip voltage of the current sense comparator
(internal reference or analog input voltage of 2V is used)
0000
0%
0V
0001
6.7%
23 mV
0010
13.3%
45 mV
CA3..0 / CB3..0
...
(bridge continuously in slow decay condition)
...
1110
93.3%
317 mV
1111
100%
340 mV
The current values correspond to a standard 4 Bit DAC, where 100%=15/16. The contents of all
registers is cleared to “0” on power-on reset or disable via the ENN pin, bringing the chip to a low
power standby mode. All SPI inputs have Schmitt-Trigger function.
Base current control via INA and INB
In SPI mode, the chip can use an external reference voltage for each DAC. This allows the adaptation
to different motors. This mode is enabled by tying pin ANN to GND. A 2.0V input voltage gives full
scale current of 100%. In this case, the typical trip voltage of the current sense comparator is
determined by the input voltage and the DAC current setting (see table above) as follows:
VTRIP,A = 0.17 VINA × “percentage SPI current setting A”
VTRIP,B = 0.17 VINB × “percentage SPI current setting B”
A maximum of 3.0V VIN is possible. Multiply the percentage of base current setting and the DAC table
to get the overall coil current. It is advised to operate at a high base current setting, to reduce the
effects of noise voltages. This feature allows a high resolution setting of the required motor current
using an external DAC or PWM-DAC.
Controlling the power down mode via the SPI interface
Bit
Standard
function
Control
word
function
11
10
9
8
7
6
5
4
3
2
1
0
MxA CA3 CA2 CA1 CA0 PhA MxB CB3 CB2 CB1 CB0 PhB
-
0
0
0
0
-
-
0
0
0
0
-
Enable standby mode and
clear error flags
Programming current value “0000” for both coils at a time clears the overcurrent flags and switches the
TMC239 into a low current standby mode with coils switched off.
Open load detection
Open load is signaled, whenever there are more than 14 oscillator cycles without PWM switch off. Note
that open load detection is not possible while coil current is set to “0000”, because the chopper is off in
this condition. The open load flag will then always be read as inactive (“0”). During overcurrent
conditions, the open load flags also become active!
Overcurrent protection and diagnosis
The TMC239 uses the current sense resistors on the low side to detect an overcurrent: Whenever a
voltage above 0.61V is detected, the PWM cycle is terminated at once and all transistors of the bridge
are switched off for the rest of the PWM cycle. The error counter is increased by one. If the error
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
9
counter reaches 3, the bridge remains switched off for 63 PWM cycles and the error flag is read as
“active”. The user can clear the error condition in advance by clearing the error flag. The error counter
is cleared, whenever there are more than 63 PWM cycles without overcurrent. There is one error
counter for each of the low side bridges, and one for the high side. The overcurrent detection is
inactive during the blank pulse time for the corresponding bridge.
The high side comparator detects a short to GND or an overcurrent, whenever the voltage between VS
and VT becomes higher than 0.15 V at any time, except for the blank time period which is logically
ORed for both bridges. Here all transistors become switched off for the rest of the PWM cycle,
because the bridge with the failure is unknown.
The overcurrent flags can be cleared by disabling and re-enabling the chip either via the ENN pin or by
sending a telegram with both current control words set to “0000”. In high side overcurrent conditions
the user can determine which bridge sees the overcurrent, by selectively switching on only one of the
bridges with each polarity (therefore the other bridge should remain programmed to “0000”).
Overtemperature protection and diagnosis
The circuit switches off all output power transistors during an overtemperature condition. The overtemperature flag should be monitored to detect this condition. The circuit resumes operation after cool
down below the temperature threshold.
Enable pin behavior
During disable conditions the circuit switches off all output power transistors and goes into a low
current shutdown mode. All register contents is cleared to “0”, and all status flags are cleared.
Chopper cycle
The TMC239 uses a quiet fixed frequency chopper. Both coils are chopped with a phase shift of 180
degrees. The mixed decay option is realized as a self stabilizing system (pat. fi.), by shortening the fast
decay phase, if the ON phase becomes longer. It is advised to enable this for each phase during the
second half of each microstepping half-wave, when the current is meant to decrease. This leads to
less motor resonance, especially at medium velocities. With low velocities or during standstill mixed
decay should be switched off. The mixed decay mode can also be enabled when output current is near
to zero, to reduce the minimum motor current which can be achieved.
When polarity is changed on one bridge, the PWM cycle on that bridge becomes restarted at once.
Fast decay switches off both upper transistors, while enabling the lower transistor opposite to the
selected polarity. Slow decay always enables both lower side transistors.
target current phase A
actual current phase A
on
slow decay
on
fast decay
slow decay
oscillator clock
resp. external clock
mixed decay disabled
mixed decay enabled
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
10
Blank time
The TMC239 uses a digital blanking pulse for the current chopper comparators. This prevents current
spikes, which can occur during switching action due to capacitive loading, from terminating the
chopper cycle. The lowest possible blanking time gives the best results for microstepping: A long blank
time leads to a long minimum turn-on time, thus giving an increased lower limit for the current. Please
remark, that the blank time should cover both, switch-off time of the lower side transistors and turn-on
time of the upper side transistors plus some time for the current to settle. Thus the complete switching
duration should never exceed 1.5µs. With slow external power stages it will become necessary to add
additional RC-filtering for the sense resistor inputs.
The TMC239 allows to adapt the blank time to the load conditions and to the selected slope in four
steps:
Blank time settings
BL2
BL1
Typical blank time
GND
GND
0.6 µs
GND
VCC
0.9 µs
VCC
GND
1.2 µs
VCC
VCC
1.5 µs
Standby and shutdown mode
The circuit can be put into a low power standby mode by the user, or, automatically goes to standby on
Vcc undervoltage conditions. Before entering standby mode, the TMC239 switches off all power
transistors, and holds their gates in a disable condition using high ohmic resistors. In standby mode the
oscillator becomes disabled and the oscillator pin is held at a low state. The standby mode is available
via the interface in SPI-mode and via the ENN pin in non-SPI mode.
The shutdown mode can only be entered in SPI-mode using the ENN pin. In shutdown all internal
reference voltages also become switched off and the SPI circuit is held in reset.
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
11
Classical non-SPI control mode (stand alone mode)
The driver can be controlled by analog current control signals and digital phase signals. To enable this
mode, tie pin SPE to GND. In this mode, the SPI interface is disabled and the SPI input pins have
alternate functions. The internal DACs are forced to “1111”.
Pin functions in stand alone mode
Pin
Stand alone
mode name
SPE
Function in stand alone mode
Tie to GND to enable stand alone mode
ANN
MDAN
Enable mixed decay for bridge A (low = enable)
SCK
MDBN
Enable mixed decay for bridge B (low = enable)
SDI
PHA
Polarity bridge A (low = current flow from output OA1 to OA2)
CSN
PHB
Polarity bridge B (low = current flow from output OB1 to OB2)
SDO
ERR
Error output (high = overcurrent on any bridge, or overtemperature). In this
mode, the pin is never tristated.
ENN
Standby mode (high active), high causes a low power mode of the device.
Setting this pin high also resets all error conditions.
INA,
INB
Current control for bridge A, resp. bridge B. Refer to AGND. The sense
resistor trip voltage is 0.34V when the input voltage is 2.0V. Maximum input
voltage is 3.0V.
Input signals for microstep control in stand alone mode
INA
INB
90°
180°
270°
PHA
(SDI)
PHB
(CSN)
MDAN
(ANN)
MDBN
(SCK)
Use dotted line to improve performance
at medium velocities
Copyright © 2002, TRINAMIC Microchips GmbH
360°
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
12
Unipolar operation
The TMC239 can also be used in an unipolar motor application with microstepping. In this
configuration, only the four upper power transistors are required.
Differences of short circuit behavior in unipolar operation mode
Since there is no possibility to disable a short to VS condition, the circuit is not completely short circuit
proof. In a low cost application a motor short would be covered, just using the bottom sense resistors
(see schematic).
Differences in chopper cycle in unipolar operation mode
In unipolar mode, one of the upper side transistors is chopped, depending on the phase polarity. Slow
decay mode always means, that both transistors are disabled. There is no difference between slow
and fast decay mode, and the mixed decay control bits are “don’t care”. The transistors have to stand
an off voltage, which is slightly higher than the double of the supply voltage. Voltage decay in the coil
can be adapted to the application by adding additional diodes and a zener diode to feed back coil
current in flyback conditions to the supply.
+VM
HA1
TMC239
HA2
P
P
One coil of
the motor
LA2
LA1
SRA
RS
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
13
Calculation of the external components
Sense resistor
Choose an appropriate sense resistor (RS) to set the desired motor current. The maximum motor
current is reached, when the coil current setting is programmed to “1111”. This results in a current
sense trip voltage of 0.34V when the internal reference or a reference voltage of 2V is used.
When operating your motor in fullstep mode, the maximum motor current is as specified by the
manufacturer. When operating in sinestep mode, multiply this value by 1.41 for the maximum current
(Imax).
RS = VTRIP / Imax
In a typical application:
RS = 0.34V / Imax
RS:
VTRIP:
Imax:
Current sense resistor of bridge A, B
Programmed trip voltage of the current sense comparators
Desired maximum coil current
Examples for sense resistor settings
RS
0.47Ω
0.33Ω
0.22Ω
Imax
723mA
1030mA
1545mA
High side overcurrent detection resistor RSH
The TMC239 detects an overcurrent to ground, when the voltage between VS and VT exceeds 150mV.
The high side overcurrent detection resistor should be chosen in a way that 100mV voltage drop are
not exceeded between VS and VT, when both coils draw the maximum current. In a sinestep
application, this is when sine and cosine wave have their highest sum, i.e. at 45 degrees,
corresponding to 1.41 times the maximum current setting for one coil. In a fullstep application this is
the double coil current.
In a microstep application:
RSH = 0.1V / (1.41 × Imax)
In a fullstep application:
RSH = 0.1V / (2 × Imax)
RSH:
Imax:
High side overcurrent detection resistor
Maximum coil current
However, if the user desires to use higher resistance values, a voltage divider in the range of 10Ω to
100Ω can be used for VT. This might also be desired to limit the peak short to GND current, as
described in the following chapter.
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
14
Making the circuit short circuit proof
In practical applications, a short circuit does not describe a static condition, but can be of very different
nature. It typically involves inductive, resistive and capacitive components. Worst events are
unclamped switching events, because huge voltages can build up in inductive components and result
in a high energy spark going into the driver, which can destroy the power transistors. The same is true
when disconnecting a motor during operation: Never disconnect the motor during operation!
There is no absolute protection against random short circuit conditions, but pre-cautions can be taken
to improve robustness of the circuit:
In a short condition, the current can become very high before it is interrupted by the short detection,
due to the blanking during switching and internal delays. The high-side transistors allow full current
flowing for the selected blank time. The lower the external inductivity, the faster the current climbs. If
inductive components are involved in the short, the same current will shoot through the low-side
resistor and cause a high negative voltage spike at the sense resistor. Both, the high current and the
voltage spikes are a danger for the driver and transistors.
Thus there are a two things to be done, if short circuits are expected:
1. Protect SRA/SRB inputs using a series resistance
2. Increase RSH to limit maximum transistor current: Use same value as for sense resistors
The second measure effectively limits short circuit current, because the upper driver transistor with its
fixed ON gate voltage of 7V forms a constant current source together with its internal resistance and
RSH. A positive side effect is, that only one type of low ohmic resistor is required. The drawback is, that
power dissipation increases. The schematic shows the modifications to be done.
However, the effectiveness of these measures should be tested in the given application.
VS
R2
RSH
100nF
VT
+VM
100R
GND
TMC236 /
TMC239
RSH=RSA=RSB
Microstep: R2 = 27R
Fullstep: R2 = 18R
CVM
SRA
100R
SRB
100R
RSA
RSB
GND
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
15
Oscillator capacitor
The PWM oscillator frequency can be set by an external capacitor. The internal oscillator uses a 28kΩ
resistor to charge / discharge the external capacitor to a trip voltage of 2/3 Vcc respectively 1/3 Vcc. It
can be overdriven using an external CMOS level square wave signal. Do not set the frequency higher
than 100kHz and do not leave the OSC terminal open! The two bridges are chopped with a phase shift
of 180 degrees at the positive and at the negative edge of the clock signal.
1
fOSC ≈
40 µs × COSC [nF]
fOSC:
COSC:
PWM oscillator frequency
Oscillator capacitor in nF
Table of oscillator frequencies
fOSC typ.
16.7kHz
20.8kHz
25.0kHz
30.5kHz
36.8kHz
COSC
1.5nF
1.2nF
1.0nF
820pF
680pF
Please remark, that an unnecessary high frequency leads to high switching losses in the power
transistors and in the motor.
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
16
Slope Control Resistor
The output-voltage slope of the full bridge is controlled by a constant current gate charge / discharge of
the MOSFETs. The charge / discharge current for the high-side MOSFETs can be controlled by an
external resistor: A reference current is generated by internally pulling the SLP-Pin to 1.25V via an
integrated 4.7KΩ resistor. This current is used to generate the current for switching ON and OFF the
upper side transistors.
The gate-driver output current can be set in range of 0.5mA to 25mA by an external resistor:
RSLP [kΩ] ≈
RSLP:
IOUT:
123
− 4 .7
IOUT [mA]
Slope control resistor
Controlled output current of the low-side MOSFET driver
The SLP-pin can directly be connected to AGND for the fastest output-voltage slope (respectively
maximum output current).
The low side MOSFETs are switched on/off with a constant current of typ. +/-15mA into their gate for
charge and discharge.
Slope control only affects the upper transistors, and thus the normal direction current, where the circuit
feeds energy into the coils. The additional mixed decay slopes, where the coil feeds back current into
the power supply, have fixed slope control (corresponding to a 5KΩ to 10KΩ slope control resistor). For
applications where electromagnetic emission is very critical, it might be necessary to add additional LC
(or capacitor only) filtering on the motor connections.
For these applications emission is lower, if only slow decay operation is used.
Please remark, that there is a trade off between reduced electromagnetic emissions (slow slope) and
high efficiency because of low dynamic losses (fast slope).
25
IHDON
20
-IHDOFF
15
10
5
0
0
2
5
10
RSLP in KOhm
Copyright © 2002, TRINAMIC Microchips GmbH
20
50
100
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
17
Absolute Maximum Ratings
The maximum ratings may not be exceeded under any circumstances.
Symbol Parameter
Min
Max
Unit
VS
Bridge supply voltage
35
V
VSM
Bridge voltage spike / max. 20000s
40
V
VCC
Logic supply voltage
6.0
V
IOP
Gate driver peak current (1)
50
mA
VI
Logic input voltage
-0.3
VCC+0.3V
V
VIA
Analog input voltage
-0.3
VCC+0.3V
V
IIO
Maximum current to / from digital pins
+/-10
mA
VS-1V
VS+0.3V
V
-0.5
and analog inputs
VVT
Short-to-ground detector input voltage
TJ
Junction temperature
-40
150
°C
TSTG
Storage temperature
-55
150
°C
(1) Internally limited
Electrical Characteristics
Operational Range
Symbol Parameter
Min
Max
Unit
TAI
Ambient temperature industrial (1) TMC 239
-25
125
°C
TAA
Ambient temperature automotive TMC 239
-40
125
°C
TJ
Junction temperature
-40
140
°C
VS
Bridge supply voltage
7
30
V
VCC
Logic supply voltage
3.1
5.5
V
fCLK
Chopper clock frequency
100
kHz
(1) The circuit can be operated up to 140°C, but output power might derate.
Copyright © 2002, TRINAMIC Microchips GmbH
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
18
DC Characteristics
DC characteristics contain the spread of values guaranteed within the specified supply voltage and
temperature range unless otherwise specified. Typical characteristics represent the average value of
all parts.
Logic supply voltage: VCC = 3.0 V ... 5.5 V,
Junction temperature: TJ = -40°C … 140°C,
Bridge supply voltage : VS = 7 V…30 V
(unless otherwise specified)
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
ILDON
Gate drive current
low side switch ON
VLD < 4V
8.5
12
20
mA
ILDOFF5
Gate drive current
low side switch OFF
VLD > 3V
-15
-25
-35
mA
Gate drive current
low side switch OFF
VLD > 3V
-10
-15
-20
mA
Gate drive current
high side switch ON
RSLP= 0K
-20
-22.5
-35
mA
Gate drive current
high side switch OFF
RSLP= 0K
15
22.5
25
mA
VGH1
Gate drive voltage high side ON
VS > 8V
-5.1
-6
-8
V
VGL1
Gate drive voltage low side ON
VS > 8V
5.1
6.1
8
V
VGH0
Gate drive voltage high side OFF
0
-0.5
V
VGL0
Gate drive voltage low side OFF
0
0.5
V
VGCL
Gate driver clamping voltage
-IH / IL = 20mA
16
20
V
VGCLI
Gate driver inverse clamping
voltage
-IH / IL = -20mA
VCCUV
VCC undervoltage
2.5
2.7
2.9
V
VCCOK
VCC voltage o.k.
2.7
2.9
3.1
V
0.5
0.7
1.1
mA
0.43
0.7
mA
<1
20
µA
ILDOFF3
IHDON
IHDOFF
ICC
VCC supply current
VCC = 5V
VCC = 3.3V
VS - VHD < 4V
VS - VHD > 2V
fosc = 25 kHz
12
-0.8
V
ICCSTB
VCC supply current standby
ICCSD
VCC supply current shutdown
VSUV
VS undervoltage
5.5
5.9
6.2
V
VCCOK
VS voltage o.k.
6.1
6.4
6.7
V
ENN = 1
ISSD
VS supply current shutdown or
standby
VS = 14V
VIH
High input voltage
(all digital inputs)
2.2
VCC +
0.3 V
V
VIL
Low input voltage
(all digital inputs)
-0.3
0.7
V
VIHYS
Input voltage hysteresis
(all digital inputs)
100
300
500
mV
VOH
High output voltage
(output SDO)
-IOH = 1mA
VCC –
0.6
VCC –
0.2
VCC
V
VOL
Low output voltage
(output SDO)
IOL = 1mA
0
0.1
0.4
V
Copyright © 2002, TRINAMIC Microchips GmbH
28
µA
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
-IISL
-IIEL
19
Low input current
(all digital inputs)
VI = 0
VCC = 3.3V
VCC = 5.0V
2
Low input current
(input ENN)
VI = 0
VCC = 3.3V
VCC = 5.0V
10
70
µA
µA
µA
50
µA
µA
µA
10
25
20
30
VOSCH
High input voltage threshold
(input OSC)
tbd
2/3 VCC
tbd
V
VOSCL
Low input voltage threshold
(input OSC)
tbd
1/3 VCC
tbd
V
VVTD
VT threshold voltage
-130
-155
-180
mV
(referenced to VS)
VSRT
SRA / SRB 100% setting
threshold using internal
reference or 2V at INA / INB
311
345
380
mV
VSRS
SRA / SRB overcurrent detection
threshold
570
615
660
mV
-6
0
6
mV
200
264
300
kΩ
VSROFFS
RINAB
SRA / SRB comparator offset
voltage
INA / INB input resistance
Vin ≤ 3 V
AC Characteristics
AC characteristics contain the spread of values guaranteed within the specified supply voltage and
temperature range unless otherwise specified. Typical characteristics represent the average value of
all parts.
Logic supply voltage: VCC = 3.3V,
Bridge supply voltage: VS = 14.0V,
Ambient temperature: TA = 27°C,
External MOSFET gate capacity = 3.2nC
Symbol Parameter
fOSC
TBL
TONMIN
Conditions
Min
Typ
Max
Unit
20
25
31
kHz
using internal oscillator
COSC = 1nF
±1%
Blank time
BL1, BL2 = VCC
1.35
1.5
1.65
µs
Minimum PWM on-time
BL1,BL2 =
GND
Oscillator frequency
0.7
µs
Thermal Protection
Symbol
TJOT
TJOTHYS
TJWT
TJWTHYS
Parameter
Conditions
Thermal shutdown
Min
Typ
Max
Unit
143
150
160
°C
TJOT hysteresis
Prewarning temperature
TJWT hysteresis
Copyright © 2002, TRINAMIC Microchips GmbH
10
133
141
19
°C
151
°C
°C
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
20
Interface Timing
tES
ENN
CSN
t1
tCL
tCH
t1
t1
SCK
tDU
SDI
bit11
tDH
bit10
bit0
tD
SDO
tZC
bit11
bit10
bit0
Propagation times
(3.0 V ≤ VCC ≤ 5.5 V, -40°C ≤ Tj ≤ 150°C; VIH = 2.8V, VIL = 0.5V; tr, tf = 10ns; CL = 50pF,
unless otherwise specified)
Symbol
fSCK
Parameter
Conditions
Min
ENN = 0
DC
SCK frequency
Typ
Max
Unit
4
MHz
t1
SCK stable before and after
CSN change
50
ns
tCH
Width of SCK high pulse
100
ns
tCL
Width of SCK low pulse
100
ns
tDU
SDI setup time
40
ns
tDH
SDI hold time
50
ns
tD
SDO delay time
tZC
CSN high
impedance
tES
ENN to SCK setup time
to
CL = 50pF
SDO
37
high
Copyright © 2002, TRINAMIC Microchips GmbH
50
tbd
80
ns
ns
µs
TMC239 DATA SHEET (V1.00 / Apr. 24th, 2003)
21
Application note: Extending the microstep resolution
For some applications it might be desired to have a higher microstep resolution, while keeping the
advantages of control via the serial interface. The following schematic shows a solution, which adds
two LSBs by selectively pulling up the SRA / SRB pin by a small voltage difference. It assumes a full
scale sense voltage of 340mV. The circuit still takes advantage of completely switching off of the coils
when the internal DAC bits are set to “0000”. This results in the following comparator trip voltages:
Current setting
Trip voltage
(MSB first)
0000xx
0V
000111
5.8 mV
000110
11.5 mV
000101
17.3 mV
000100
23 mV
...
111101
334.2 mV
111100
340 mV
SPI bit
DAC bit
SPI bit
DAC bit
15
/B1
7
A2
14
/B0
6
PHA
13
/A1
5
MDB
12
/A0
4
B5
11
MDA
3
B4
10
A5
2
B3
9
A4
1
B2
SCK
SCK
SDI
SDI
TMC236 /
TMC239
SDO
SRA
110R
4.7nF
opt.
CSN
/CS
47K
47K
47K
+VCC
100K
/OE
C2
/MR
C1
DS1D
Q0
Q1
Q2
Q3
Q4
Q5
Q6
Q7
/DACA.0
/DACA.1
/DACB.0
/DACB.1
Free for
second
TMC239
Q7'
74HC595
Vcc = 5V
C
SDO
Q
D
1/2 74HC74
i
SPI is a trademark of Motorola
Copyright © 2002, TRINAMIC Microchips GmbH
RS
8
A3
0
PHB