LB1843V Motor Driver IC Application Note

LB1843V
Monolithic Digital IC
Low-saturation,
current-controlled
bidirectional motor driver
Application Note
http://onsemi.com
Overview
The LB1843V is a low-saturation bidirectional motor driver with output current limitation and detection
functions. This design is ideal for controlling the loading motor in a video camera.
Function
 Output current limiter and detector built in.
 Low-saturation voltage bidirectional bridge circuit built in: VOsat = 0.40 V typ. at 400 mA.
 Practically no current drain (0.1 μA or less) in standby mode.
 Input-linked reference voltage built in . Thermal shutdown circuit built in.
 Requires little space, since few external components are needed and the IC is contained in a small
SSOP-20 package
Typical Applications
 Toy
 Portable Printer
 Battery Operated Devices
 Camera
 Scanner
Package Dimensions
unit : mm (typ)
Semiconductor Components Industries, LLC, 2013
December, 2013
1/17
LB1843V Application Note
Pin Assignment
Application Circuit Example
2/17
LB1843V Application Note
Cautions:
VCC and P-GND lines suffer substantial fluctuation in the current quantity, causing a problem of line oscillation
in certain cases. In this case, take following points into account:
(1) Use a thick and short wiring to reduce the wiring inductance.
(2) Insert a capacitor with satisfactory frequency characteristics near IC.
*) Electrostatic capacitor (10uF) is used to stabilize power. Requirement for capacitance value varies
depends on substrate wiring, motor, and power. The recommendation range of the capacitor is
approximately 0.1μF to 10μF.
Please check supply voltage waveform when motor is under operation and use a capacitor for stable
operation.
(3) Connect S-GND to the control system GND on the CPU side and P-GND to the power system GND.
Sample Application Timing Chart
Sample application timing chart
1) Connect a DC motor (RL = R) between OUT1 and OUT2, and with the RD pin pulled up, input a forward
rotation signal (IN1 = high, IN2 = low).
Because the output is used in the saturated state at startup, set the DEL input to low.
2) The DC motor starts up, and the startup current (IST = VM/R) flows to the motor.
3) The DC motor rotates in the normal state. At this point, set the DEL input to high.
4) If the DC motor locks, the motor current IM increases to the point of Ilimit (= VLIR/(10Rf)), the output current
limiter operates to limit the output current. At the same time, RD is output low from the set current detection
circuit.
3/17
LB1843V Application Note
Reference voltage (Vref)
The Vref output is linked to the input; if either IN1 or IN2 is high, the reference voltage is output.
Output current limiter
The schematic for the output current limiter is shown below.
The output set current is set according to the reference voltage VLIR applied to the LIR pin. When VLIR is
applied, 1/10 of that voltage is generated at both ends of RS in the diagram; this voltage is input on the positive
(+) side of the current setting amplifier.
The motor current IM generates voltage equal to (IM ´ Rf) at both ends of the external resistor Rf. This
voltage is input to the negative (–) side of the same amplifier, and the differential amplifier functions and the
output transistors are driven so that these inputs become equal.
The set current value in this instance is determined by the following equation:
Ilimit = VLIR/(10Rf) [A]
Set current detector
(1) When DEL = high
If the motor current IM has not reached the set current Ilimit, the input voltage on the negative (–) side of
the amplifier is greater than the input voltage on the positive (+) side. As a result, the drive current
increases and the output PNP transistors reach the saturation state. If this state is detected, the detection
signal is sent to the set current detector, and the RD output goes high.
If the motor current IM reaches the set current Ilimit, the output PNP transistor enters the controlled state,
and the RD output goes low.
(2) When DEL = low
Because the operation of the current setting amplifier is cancelled when a low signal is input to the DEL pin,
the output PNP transistors reach the saturation state and the RD output goes high, just as in the case
described above.
The following table summarizes the states described above.
DEL
OUT output
RD
Limit
L
Non-limit
Off
Saturated
Off
H
L
Output Current Limiter and Set Current Detector Block Diagram
4/17
LB1843V Application Note
Specifications
Absolute Maximum Ratings at Ta = 25C
Parameter
Maximum supply voltage
Output current
Applied input voltage
Allowable power dissipation
Symbol
Conditions
Ratings
Unit
VCC max
10.5
V
Im max
800
mA
VIN
Pd max
-0.3 to +10
With board (50x35x1.6mm)
V
800
mW
Operating temperature
Topr
-20 to +80
C
Storage temperature
Tstg
-40 to +150
C
Caution 1) Absolute maximum ratings represent the value which cannot be exceeded for any length of time.
Caution 2) Even when the device is used within the range of absolute maximum ratings, as a result of continuous usage
under high temperature, high current, high voltage, or drastic temperature change, the reliability of the IC may
be degraded. Please contact us for the further details.
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed,
damage may occur and reliability may be affected.
Recommended Operating Conditions at Ta = 25C
Ratings
Parameter
Symbol
Conditions
Unit
min
Supply voltage
typ
max
VCC
3.0
9.0
V
VM voltage
VM
2.2
VCC
V
High-level input voltage
VIH
3.0
9.0
V
Low-level input voltage
VIL
-0.3
+0.7
V
LIR input voltage
VLIR
0.5
VCC-1.0
Output current limitation
I limit
50
350
V
mA
Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses beyond the Recommended
Operating Ranges limits may affect device reliability.
Electrical Characteristics at Ta  25C, VCC = 7.2V
Ratings
Parameter
Symbol
Conditions
Unit
min
Supply current
ICC0
During standby
ICC1
During bidirectional operation, no load
ICC2
During braking
Output saturation voltage
Vsat1
(upper side + lower side)
typ
max
0.1
10
A
9
13
mA
12
18
mA
IO = 200mA
0.20
0.30
V
Vsat2
IO = 400mA
0.40
0.60
V
Reference voltage
Vref
Ivref = 1mA
1.85
2.0
2.15
V
Set output current
I limit
Resistance between VCC and VM=1Ω,
165
185
205
mA
90
150
A
0.3
V
When LIR=2V
Input current
RD saturation voltage
IIN
VIN = 5V
VRDsat
IO = 1mA
Output current limit is determined by the following equation (Rf is the sensing resistance between V CC and VM):
I limit = VLIR / 10Rf (A)
The input range for VLIR is 0.5 to VCC – 1.0(V)
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be
indicated by the Electrical Characteristics if operated under different conditions.
5/17
LB1843V Application Note
Pin Functions
Pin No.
Pin name
Pin Function
13
IN1
Control signal input pin
14
IN2
Control signal input pin
Equivalent Circuit
VCC
50K
80K
4K
S-GND
15
DEL
Control signal input pin
VCC
62K
82K
S-GND
4,5
VM
Output current detect pin
2,3
OUT1
Out pin
18,19
OUT2
Out pin
VM
P-GND
Continued on next page.
6/17
LB1843V Application Note
Continued from preceding page.
9
Vref
Reference voltage output pin
VCC
5.6K
10K
12K
S-GND
12
RD
Lock detect signal output pin
12K
S-GND
17
LIR
Output current setting pin
VCC
200
S-GND
6
VCC
Power supply voltage pin
11
S-GND
Signal ground pin
1,20
P-GND
Power ground pin
NC
No connect
7,8,10,16
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LB1843V Application Note
Truth Table
Input
Output
Mode
IN1
IN2
OUT1
OUT2
L
L
Off
Off
H
L
H
L
Standby
Forward
L
H
L
H
Reverse
H
H
L
L
Brake
Output Current Limitation and Detector Output
DEL
OUT output
RD
Limit
L
Non-limit
Off
Saturated
Off
H
L
Operation explanation
 Output stage transistor function
VM
VM
OFF
OFF
OFF
OFF
(Standby)
ON
OFF
(Forward)
VM
OFF
OFF
ON
ON
VM
ON
OFF
(Reverse)
OFF
OFF
ON
ON
(Brake)
 Thermal protection function
LB1843V incorporates thermal shutdown circuitry. When junction temperature Tj exceeds 180C, the output
current flowing between OUT1 and OUT2 is reduced; therefore, the heat generation is reduced.
The thermal shutdown circuit does not guarantee the protection of the final product because it operates when
the temperature exceed the junction temperature of Tjmax=150C.
8/17
16
160
14
140
12
120
10
100
IIN(uA)
Icc(mA)
LB1843V Application Note
8
6
80
60
DEL=H
DEL=L
Brake
4
2
40
20
0
0
0
1
2
3
4
5
6
7
8
0
9
1
2
3
4
5
6
7
8
9
VIN (V)
Vcc (V)
Figure 1 Icc vs Vcc (VIN=3V,LIR=Vref,Rf=0.5ohm,no load)
Figure 2 IIN vs VIN (Vcc=6V)
600
400
500
300
Ilimit(mA)
Ilimit(mA)
400
300
200
100
Rf=1.0ohm
100
200
Ilimit=100mA
Ilimit=200mA
Ilimit=300mA
Rf=0.5ohm
0
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0.0
1.0
2.0
VLIR(V)
3.0
4.0
5.0
6.0
7.0
8.0
9.0
Vcc(V)
Figure 3 Ilimit vs VLIR (Vcc=6.0V,RL=10ohm)
Figure 4 Ilimit vs Vcc (VIN=3V,DEL=3V,RL=10ohm,Rf=0.5ohm)
0.6
0.4
0.5
0.3
Vsat (V)
Vsat (V)
0.4
0.3
0.2
0.2
0.1
0.1
Io=400mA
0.0
0
100
200
300
400
500
600
Io (mA)
Figure 5 Vsat vs Io (Vcc=6V,VIN=3V,DEL=L,LIR=Vref)
700
Io=200mA
0.0
-50
0
50
100
150
Ta (deg)
Figure 6 Vsat)vs Temperature (Vcc=6V,VIN=3V,DEL=L,LIR=Vref)
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LB1843V Application Note
2.5
0.6
0.5
2.0
Vref (V)
VRDsat (V)
0.4
0.3
0.2
1.5
1.0
0.5
0.1
0.0
0
1
2
3
4
5
6
7
8
9
Io (mA)
Figure 7 VRDsat vs Io (Vcc=6V,VIN=3V,DEL=H,LIR=Vref)
10
0.0
0
1
2
3
4
5
6
7
8
9
Vcc (V)
Figure 8 Vref vs Vcc (VIN=3V)
10/17
LB1843V Application Note
Waveform example
*Please refer to the following test circuit diagram 1.
 No load VCC=3V IN2=“L”
High
 No load VCC=3V IN1=“H”
High
Low
High
High
Off
Low
Off
Low
Ch1
IN1
10V/div
High
Ch2
VOUT1
1V/div
Low
Ch3
VOUT2
1V/div
Low
High
Ch1
IN2
10V/div
High
Low
Ch2
VOUT1
1V/div
Low
Low
Low
T=2ms/div
T=50ms/div
 No load VCC=6V IN2=“L”
High
 No load VCC=6V IN1=“H”
High
Low
High
High
Off
Low
Off
Low
Ch1
IN1
10V/div
High
Ch2
VOUT1
2V/div
Low
Ch3
VOUT2
2V/div
Low
High
Ch1
IN2
10V/div
High
Low
Ch2
VOUT1
2V/div
Low
Low
Low
 No load VCC=3V IN1=“H”
Time scale expansion
High
Ch3
VOUT2
2V/div
T=2ms/div
T=50ms/div
Low
Ch3
VOUT2
1V/div
“fall time”
High
Ch1
IN2
10V/div
Low
Ch2
VOUT1
1V/div
 No load VCC=3V IN1=“H”
Time scale expansion
“rise time”
Low
High
Low
High
Ch1
IN1
10V/div
Ch2
VOUT1
1V/div
t=1.7us
t=0.5us
Low
Low
T=1us/div
Ch3
VOUT2
1V/div
Low
Low
Ch3
VOUT2
1V/div
T=1us/div
11/17
LB1843V Application Note
 No load VCC=6V IN1=“H”
Time scale expansion
Low
High
 No load VCC=6V IN1=“H”
Time scale expansion
“fall time”
High
Ch1
IN2
10V/div
Low
Ch2
VOUT1
2V/div
“rise time”
Low
High
Low
Ch1
IN1
10V/div
Ch2
VOUT1
2V/div
High
t=1.5us
t=0.5us
Low
Ch3
VOUT2
2V/div
Low
Low
T=1us/div
 No load VCC=9V IN1=“H”
Time scale expansion
Low
High
Ch3
VOUT2
2V/div
Low
T=1us/div
 No load VCC=9V IN1=“H”
Time scale expansion
“fall time”
High
Ch1
IN2
10V/div
Low
Ch2
VOUT1
2V/div
“rise time”
Low
High
Low
High
Ch1
IN1
10V/div
Ch2
VOUT1
2V/div
t=1.5us
t=0.6us
Low
Ch3
VOUT2
2V/div
Low
Low
Low
T=1us/div
Ch3
VOUT2
2V/div
T=1us/div
(Test circuit diagram 1)
0.01uF
10uF
+
VCC=3V
/6V/9V
1 P-GND
P-GND 20
2 OUT1
OUT2 19
3 OUT1
OUT2 18
4 VM
5 VM
6 VCC
LB1843V
1Ω
LIR 17
(NC) 16
DEL 15
7 (NC)
IN2 14
8 (NC)
IN1 13
9 Vref
RD 12
10 (NC)
S-GND 11
VIN1=5V
(f=5Hz or 100Hz,
duty=50%)
"H"
"L"
VIN2=5V
12/17
LB1843V Application Note
*Please refer to the following test circuit diagram 2.
 DC motor load VCC=3V IN2=“L”
Current waveform example
Low
“motor start”
Ch1
IN1
10V/div
High
Ch2
VOUT1
2V/div
High
Off
Off
Ch3
VOUT2
2V/div
Low
Ch4
Icoil
200mA/div
Forward
Standby
T=20ms/div
When DC motor starts up, the current value becomes high. However, rotation of DC motor starts, induced
voltage Ea is generated and current decreases according to the rotation frequency.
If a coil resistance is set to Rcoil and motor voltage is set to VCC, then motor current is obtained as follows:
Im = (VCC-Ea)/Rcoil.
 DC motor load VCC=3V IN1=“H”
Current waveform example
High
Low
“brake current”
High
High
Low
Low
Low
Low
Ch1
IN2
5V/div
Ch2
VOUT1
2V/div
Low
Ch3
VOUT2
2V/div
Brake
Brake
Ch4
Icoil
200mA/div
Forward
T=20ms/div
When DC motor is under rotation, if brake mode is set, then DC motor becomes short-brake status, and speed
falls rapidly.
In this case, current Im (Im = Ea / Rcoil) flows to the opposite direction by the induced voltage Ea generated
during motor rotation. If DC motor stops rotation, then Ea=0, and current becomes 0.
13/17
LB1843V Application Note
 DC motor load VCC =3V
Current waveform example
“active reverse brake current”
High
High
Low
High
Low
Ch1
IN1
5V/div
Low
Ch2
IN2
5V/div
High
Low
High
Ch3
VOUT1
2V/div
Brake
Reverse
Forward
Ch4
Icoil
200mA/div
T=20ms/div
If rotation direction is switched while DC motor is rotating, then torque of reverse-rotation is generated, the
speed of motor rotation becomes slow and reverse rotation is performed.
In this case, since voltage of VCC is added to induced voltage Ea generated during motor rotation, the motor
current flows into the motor coil which is obtained as follows: Im= (VCC+Ea) / Rcoil.
When you switch from forward to reverse, if the current exceeds Iomax, make sure to set brake mode until the
induced voltage is reduced between forward and reverse.
(Test circuit diagram 2)
M
Icoil
0.01uF
10uF
+
VCC=3V
1 P-GND
P-GND 20
2 OUT1
OUT2 19
3 OUT1
OUT2 18
4 VM
5 VM
6 VCC
LB1843V
1Ω
LIR 17
(NC) 16
DEL 15
7 (NC)
IN2 14
8 (NC)
IN1 13
9 Vref
RD 12
10 (NC)
S-GND 11
VIN1=5V
(f=1Hz or 5Hz, duty=50%)
"H"
"L"
VIN2=5V
14/17
LB1843V Application Note
Evaluation board description
R1:
Output current detective resistor
：1ohm
C2:
Output noise reject capacitor
：0.01uF
M
VCC
(Power Supply)
VIN
(Power Supply)
Logic input
C1:
VCC Bypass capacitor
（Electrolytic capacitor）
：10uF
(Circuit diagram of the evaluation board)
C2
0.01uF
1 P-GND
P-GND
OUT1
10uF
C1 +
VM
2 OUT1
OUT2 19
3 OUT1
OUT2 18
4 VM
5 VM
6
VCC
7
(NC)
OUT2
LIR 17
LB1843V
IC1
R1
1Ω
VCC
P-GND 20
LIR
(NC) 16
SW3
DEL 15
DEL
SW2
IN2 14
IN2
SW1
Vref
8
(NC)
IN1 13
IN1
9
Vref
RD 12
RD
10 (NC)
S-GND 11
S-GND
VIN
*VIN terminal is a power supply input terminal for switches.
5V are to impress it and can perform the setting that is in a state by the switch operation and logic input.
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LB1843V Application Note
 Operation method
Power supply injection order: VCC  VIN
 Truth value table
Input
Output
Mode
IN1
IN2
OUT1
OUT2
L
L
Off
Off
Standby
H
L
H
L
Forward
L
H
L
H
Reverse
H
H
L
L
Brake
Recommended Soldering Footprint
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LB1843V Application Note
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