ST L6258 User Manual
high current DMOS universal motor driver
PowerSO36
Features
■ Able to drive both windings of a bipolar stepper
motor or two DC motors
■ Output current up to 1.2A each winding
■ Wide voltage range: 12V to 34V
■ Four quadrant current control, ideal for
microstepping and DC motor control
■ Precision PWM control
■ No need for recirculation diodes
■ TTL/CMOS compatible inputs
■ Cross conduction protection
■ Thermal shutdow
Description
L6258 is a dual full bridge for motor control
applications realized in BCD technology, with the
capability of driving both windings of a bipolar
stepper motor or bidirectionally control two DC
motors.
L6258
PWM controlled
Not For New Design
The power stage is a dual DMOS full bridge
capable of sustaining up to 34V, and includes the
diodes for current recirculation. The output current
capability is 1.2A per winding in continuous mode,
with peak start-up current up to 1.5A. A thermal
protection circuitry disables the outputs if the chip
temperature exceeds the safe limits.
L6258 and a few external components form a
complete control and drive circuit. It has high
efficiency phase shift chopping that allows a very
low current ripple at the lowest current control
levels, and makes this device ideal for steppers as
well as for DC motors.
Table 1. Device summary
Order Code Package Packing
L6258
(Replaced by E-L6258EX and E-
L6258EXTR)
March 2010 Doc ID 4588 Rev 10 1/32
This is information on a product still in production but not recommended for new designs.
PowerSO36 Tube
www.st.com
1
Contents L6258
Contents
1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.1 Reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 Input logic (I0 - I1 - I2 - I3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3 Phase input ( PH ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4 Triangular generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.5 Charge pump circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.6 Current control loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.7 Current control loop compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3 PWM current control loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.1 Open loop transfer function analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2 Power amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.3 Load attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.4 Error amplifier and sense amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.5 Effect of the Bemf of the current control loop stability . . . . . . . . . . . . . . . 22
4 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.1 Interference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2 Motor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.3 Unused inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.4 Notes on PCB design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5 Operation mode time diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2/32 Doc ID 4588 Rev 10
L6258 List of tables
List of tables
Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Table 2. Absolute maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Table 3. Pin functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Table 4. Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 5. Current levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Table 6. Charge pump capacitor's values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 7. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Doc ID 4588 Rev 10 3/32
List of figures L6258
List of figures
Figure 1. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 2. Pin connection (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 3. Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 4. Power bridge configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 5. Current control loop block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 6. Output comparator waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 7. Ax bode plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 8. Aloop bode plot (uncompensated) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 9. Aloop bode plot (compensated) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 10. Electrical model of the load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 11. Typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 12. Full step operation mode timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 13. Half step operation mode timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 14. 4 bit microstep operation mode timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 15. PowerSO36 mechanical data & package dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4/32 Doc ID 4588 Rev 10
L6258 Block diagram
DAC
CHARGE
PUMP
VR (VDD/2)
VCP1
PH_1
I0_1
I1_1
I2_1
VREF1
TRIANGLE
GENERATOR
TRI_CAP
ERROR
AMP
+
-
V
R
+
-
+
-
C
C
POWER
BRIDGE
1
TRI_0
TRI_180
TRI_180
TRI_0
DAC
PH_2
I0_2
I1_2
I2_2
VREF1
ERROR
AMP
+
-
V
R
+
-
+
-
C
C
POWER
BRIDGE
2
TRI_0
TRI_180
THERMAL
PROT.
OUT1A
OUT1B
R
s
SENSE1A
VBOOT
DISABLE
VS
OUT2A
OUT2B
SENSE2A
R
s
VS
EA_IN2 EA_OUT2GND
EA_IN1 EA_OUT1VCP2
VDD(5V)
D96IN430D
VR GEN
INPUT
&
SENSE
AMP
C
P
C
FREF
C
BOOT
INPUT
&
SENSE
AMP
I3_1
I3_2
SENSE1B
SENSE2B
R
C1
R
1
1M
R
2
1M
R
C2
C
C2
C
C1
1 Block diagram
Figure 1. Block diagram
Table 2. Absolute maximum rating
Parameter Description Value Unit
Supply voltage 36 V
Logic supply voltage 7 V
Reference voltage 2.5 V
Output current (peak) 1.5 A
Output current (continuous) 1.2 A
Logic input voltage range -0.3 to 7 V
Bootstrap supply 60 V
s
Maximum Vgate applicable 15 V
Junction temperature 150 °C
Storage temperature range -55 to 150 °C
Doc ID 4588 Rev 10 5/32
V
V
DD
V
ref1/Vref2
I
O
I
O
V
V
boot
V
boot
T
T
stg
s
in
- V
j
Block diagram L6258
PWR_GND
PH_2
EA_IN2
EA_OUT2
DISABLE
EA_OUT1
OUT1A
EA_IN1
PH_1
SENSE1
OUT1B
I3_1
VS
I2_1
I3_2
OUT2B
SENSE2
PWR_GND
18
16
17
15
6
5
4
3
2
21
22
31
32
33
35
34
36
20
1
19
PWR_GND
PWR_GND
D96IN432E
GND
TRI_CAP
V
DD
I0_1
VREF1
I1_1
9
8
7
28
29
30
VCP1
SIG_GND
10
27
OUT2A
VCP2
VBOOT
VREF2
I2_2
I0_2
14
12
11
23
25
26
VS
I1_2
13 24
Figure 2. Pin connection (top view)
Table 3. Pin functions
Pin # Name Description
1, 36 PWR_GND
6/32 Doc ID 4588 Rev 10
2, 17 PH_1, PH_2
3I
4I
5 OUT1A Bridge output connection (1)
6 DISABLE
7TRI_cap
1_1
0_1
Ground connection (1). They also conduct heat from die to
printed circuit copper.
These TTL compatible logic inputs set the direction of
current flow through the load. A high level causes current to
flow from OUTPUT A to OUTPUT B.
Logic input of the internal DAC (1). The output voltage of the
DAC is a percentage of the Vref voltage applied according to
the thruth Table 5 on page 12.
See pin 3
Disables the bridges for additional safety during switching.
When not connected the bridges are enabled
Triangular wave generation circuit capacitor. The value of
this capacitor defines the output switching frequency
L6258 Block diagram
Table 3. Pin functions (continued)
Pin # Name Description
8V
(5V) Supply voltage input for logic circuitry
DD
9 GND Power ground connection of the internal charge pump circuit
10 V
11 V
12 V
13, 31 V
CP1
CP2
BOOT
S
Charge pump oscillator output
Input for external charge pump capacitor
Overvoltage input for driving of the upper DMOS
Supply voltage input for output stage. They are shorted
internally
14 OUT2A Bridge output connection (2)
Logic input of the internal DAC (2). The output voltage of the
15 I
0_2
DAC is a percentage of the VRef voltage applied according
to the truth Table 5 on page 12.
16 I
1_2
18, 19 PWR_GND
See pin 15
Ground connection. They also conduct heat from die to
printed circuit copper
20, 35 SENSE2, SENSE1 Negative input of the transconductance input amplifier (2, 1)
21 OUT2B
22 I
23 I
3_2
2_2
Bridge output connection and positive input of the
tranconductance (2)
See pin 15
See pin 15
24 EA_OUT_2 Error amplifier output (2)
25 EA_IN_2 Negative input of error amplifier (2)
Reference voltages for the internal DACs, determining the
26, 28 V
REF2
, V
REF1
output current value. Output current also depends on the
logic inputs of the DAC and on the sensing resistor value
27 SIG_GND Signal ground connection
29 EA_IN_1 Negative input of error amplifier (1)
30 EA_OUT_1 Error amplifier output (1)
32 I
33 I
2_1
3_1
34 OUT1B
See pin 3
See pin 3
Bridge output connection and positive input of the
tranconductance (1)
Note: The number in parenthesis shows the relevant Power Bridge of the circuit. Pins 18, 19, 1
and 36 are connected together.
Doc ID 4588 Rev 10 7/32
Block diagram L6258
Conditions
Power Dissipated
(W)
T Ambient
(˚C)
Thermal J-A resistance
(˚C/W)
5.3 70 15
4.0 70 20
2.3 70 35
pad layout + ground layers + 16 via hol
PCB ref.: 4 LAYER cm 12 x 12
pad layout + ground layers
PCB ref.: 4 LAYER cm 12 x 12
pad layout + 6cm2 on board heat sink
PCB ref.: 2 LAYER cm 12 x 12
D02IN1370
0
0
2
4
6
8
15˚C/W
20˚C/W
35˚C/W
10
12
20 40 60 80 100 120 140 160
Ambient Temperature (˚C)
Power Dissipated (W)
D02IN1371
Figure 3. Thermal characteristics
8/32 Doc ID 4588 Rev 10
Table 4. Electrical characteristics
Parameter Description Test condition Min. Typ. Max. Unit
V
V
V
V
I
I
V
S
V
DD
BOOT
Sense
S(off)
DD(off)
S(on)
S(off)
I
DD
(VS = 40V; VDD = 5V; Tj = 25°; unless otherwise specified.)
Supply voltage 12 34 V
Logic supply voltage 4.75 5.25 V
Storage voltage VS = 12 to 40V VS+6 VS+12 V
Max drop across sense
resistor
Power off reset Off threshold 6 7.2 V
Power off reset Off threshold 3.3 4.1 V
VS quiescent current
Both bridges ON, no
load
VS quiescent current Both bridges OFF 7 mA
VDD operative current 15 mA
1.25 V
15 mA
L6258 Block diagram
Table 4. Electrical characteristics (continued)
(V
= 40V; VDD = 5V; Tj = 25°; unless otherwise specified.)
S
Parameter Description Test condition Min. Typ. Max. Unit
ΔT
T
f
osc
SD-H
SD
Shut down hysteresis 25 °C
Thermal shutdown 150 °C
Triangular oscillator
frequency
TRANSISTORS
I
R
ds(on)
DSS
V
Leakage current OFF State 500 µA
On resistance ON state 0.6 0.75 W
Flywheel diode voltage If =1.0A 1 1.4 V
f
CONTROL LOGIC
V
in(H)
V
in(L)
I
in
I
dis
V
ref1/ref2
I
ref
FI =
V
ref/Vsense
V
FS
V
offset
lnput voltage All Inputs 2 V
Input voltage All inputs 0 0.8 V
Input current
Disable pin input current -10 +150 µA
Reference voltage Operating 0 2.5 V
V
ref
PWM loop transfer ratio 1.94
DAC full scale precision V
Current loop offset V
DAC factor ratio
(1)
(2)
terminal input current V
C
= 1nF 12.5 15 18.5 KHz
FREF
DD
-150 +10 µA
0 < Vin < 5V
= 1.25 -2 5 µA
ref
= 2.5V I0/I1/I2/I3 = L 1.23 1.29 1.34 V
ref
= 2.5V I0/I1/I2/I3 = H -30 +30 mV
ref
Normalized @ full scale
value
-2 +2 %
V
SENSE AMPLIFIER
V
cm
I
inp
lnput common mode
voltage range
Input bias sense1/sense2 -200 0 µA
-0.7 V
+0.7 V
S
ERROR AMPLIFIER
G
Open loop voltage gain 70 dB
V
SR Output slew rate Open loop 0.2 V/µs
GBW Gain bandwidth product 400 kHz
1. Chopping frequency is twice fosc value.
2. This is true for all the logic inputs except the disable input.
Doc ID 4588 Rev 10 9/32
Functional description L6258
2 Functional description
The circuit is intended to drive both windings of a bipolar stepper motor or two DC motors.
The current control is generated through a switch mode regulation.
With this system the direction and the amplitude of the load current are depending on the
relation of phase and duty cycle between the two outputs of the current control loop.
The L6258 power stage is composed by power DMOS in bridge configuration as it is shown
in
Figure 4, where the bridge outputs OUT_A and OUT_B are driven to Vs with an high level
at the inputs IN_A and IN_B while are driven to ground with a low level at the same inputs.
The zero current condition is obtained by driving the two half bridge using signals IN_A and
IN_B with the same phase and 50% of duty cycle.
In this case the outputs of the two half bridges are continuously switched between power
supply (V
In Figure 4 is shown the timing diagram of the two outputs and the load current for this
working condition.
Following we consider positive the current flowing into the load with a direction from OUT_A
to OUT_B, while we consider negative the current flowing into load with a direction from
OUT_B to OUT_A.
) and ground, but keeping the differential voltage across the load equal to zero.
s
Now just increasing the duty cycle of the IN_A signal and decreasing the duty cycle of IN_B
signal we drive positive current into the load.
In this way the two outputs are not in phase, and the current can flow into the load trough the
diagonal bridge formed by T1 and T4 when the output OUT_A is driven to V
OUT_B is driven to ground, while there will be a current recirculation into the higher side of
the bridge, through T1 and T2, when both the outputs are at Vs and a current recirculation
into the lower side of the bridge, through T3 and T4, when both the outputs are connected to
ground.
Since the voltage applied to the load for recirculation is low, the resulting current discharge
time constant is higher than the current charging time constant during the period in which
the current flows into the load through the diagonal bridge formed by T1 and T4. In this way
the load current will be positive with an average amplitude depending on the difference in
duty cycle of the two driving signals.
In Figure 4 is shown the timing diagram in the case of positive load current
On the contrary, if we want to drive negative current into the load is necessary to decrease
the duty cycle of the IN_A signal and increase the duty cycle of the IN_B signal. In this way
we obtain a phase shift between the two outputs such to have current flowing into the
diagonal bridge formed by T2 and T3 when the output OUT_A is driven to ground and
output OUT_B is driven to Vs, while we will have the same current recirculation conditions of
the previous case when both the outputs are driven to Vs or to ground.
So, in this case the load current will be negative with an average amplitude always
depending by the difference in duty cycle of the two driving signals.
and the output
s
In Figure 4 is shown the timing diagram in the case of negative load current.
Figure 5 shows the device block diagram of the complete current control loop.
10/32 Doc ID 4588 Rev 10
Loading...