Any and all SANYO products described or contained herein do not have specifications that can handle
applications that require extremely high levels of reliability, such as life-support systems, aircraft's
control systems, or other applications whose failure can be reasonably expected to result in serious
physical and/or material damage. Consult with your SANYO representative nearest you before using
any SANYO products described or contained herein in such applications.
SANYO assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other
parameters) listed in products specifications of any and all SANYO products described or contained
herein.
Ordering number : ENN5687B
73099TH (OT)/83097HA(OT) No. 5687-1/11
Overview
The LB1924 is a direct PWM drive output driver IC
appropriate for the power brushless motors used in office
automation equipment. It includes a speed control circuit,
an FG amplifier, and other peripheral circuits and allows a
drive circuit to be implemented with a single IC. It allows
the number of external components to be reduced by
including a lock protection circuit, a kickback absorption
diode for the lower output side, and other components on
chip.
Functions
Breakdown voltage: 30 V, output current: 3.1 A
Direct PWM drive output
Speed discriminator + PLL speed control technique
Crystal oscillator circuit
Built-in FG and integrating amplifiers
Forward/reverse switching circuit
Speed lock detection output
On-chip lower output side kickback absorption diode
Full complement of built-in protection circuits,
including lock protection, current limiter, and thermal
protection circuits
Package Dimension
unit: mm
3147B-DIP28H
1
14
28
15
0.4
0.6
4.0
4.0
27.0
20.0
R1.7
8.4
1.93
1.78
1.0
12.7
11.2
SANYO: DIP28H
[LB1924]
LB1924
SANYO Electric Co.,Ltd. Semiconductor Company
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
Power Brushless Motor Driver IC for Office
Automation Equipment
Monolithic Digital IC
No. 5687-2/11
LB1924
Parameter
Symbol
Conditions
Ratings
Unit
Maximum supply voltage
V
CC
max
30
V
V
M
max
V
CC
V
M
30
V
Output current
I
O
max
t
500 ms
3.1
A
Allowable power dissipation
Pd max1
Independent IC
3
W
Pd max2
With an arbitrarily large heat sink
20
W
Operating temperature
Topr
20 to +80
C
Storage temperature
Tstg
55 to +150
C
Specifications
Absolute Maximum Ratings
at Ta = 25C
Parameter
Symbol
Conditions
Ratings
Unit
Supply voltage range
V
CC
9.5 to 28
V
V
M
V
CC
V
M
9 to 28
V
Regulated voltage output current
I
REG
0 to 20
mA
Lock detection output current
I
LD
0 to 15
mA
Allowable Operating Conditions
at Ta = 25C
Parameter
Symbol
Conditions
Ratings
Unit
min
typ
max
Current drain
I
CC
1
31
40
mA
I
CC
2
When stopped
5.5
8.0
mA
Output saturated voltage
V
O
sat1
I
O
= 1A, V
O
(Sink) + V
O
(Source)
2.0
2.5
V
V
O
sat2
I
O
= 2A, V
O
(Sink) + V
O
(Source)
2.6
3.2
V
Output leakage current
I
O
leak
100
A
[5-V Regulated Voltage Output]
Output voltage
V
REG
I
O
= 5 mA
4.65
5.00
5.35
V
Line regulation
V
REG
1
V
CC
= 9.5 to 28 V
30
100
mV
Load regulation
V
REG
2
I
O
= 5 to 20 mA
20
100
mV
[Hall Amplifier]
Input bias current
I
HB
4
1
A
Common-mode input voltage range
V
ICM
1.5
V
REG
1.5
V
Hall input sensitivity
60
mVp-p
Hysteresis
V
IN
8
14
24
mV
Input voltage (low to high)
V
SLH
7
mV
Input voltage (high to low)
V
SHL
7
mV
[RC Oscillator]
Output high-level voltage
V
OH(CR)
2.4
2.7
3.0
V
Output low-level voltage
V
OL(CR)
1.1
1.4
1.7
V
Oscillator frequency
f
(CR)
R = 22 k
, C = 4700 pF
19
kHz
Amplitude
V
(CR)
1.0
1.25
1.5
Vp-p
[CROCK Oscillator]
Output high-level voltage
V
OH(RK)
2.5
2.8
3.1
V
Output low-level voltage
V
OL(RK)
0.5
0.8
1.1
V
External capacitor charging current
I
CHG
1
10
8
6
A
I
CHG
2
6
8
10
A
Oscillator frequency
f
(RK)
C = 0.047 F
44
Hz
Amplitude
V
(RK)
1.75
1.95
2.25
V
[Current Limiter Operation]
Limiter
V
CC
-V
M
0.45
0.5
0.55
V
[Thermal Shutdown Operation]
Thermal shutdown temperature
TSD
Design target value (junction temperature)
150
180
C
Hysteresis
TSD
Design target value (junction temperature)
40
C
Electrical Characteristics
at Ta = 25C, V
CC
= V
M
= 24 V
Continued on next page.
No. 5687-3/11
LB1924
Parameter
Symbol
Conditions
Ratings
Unit
min
typ
max
[FG Amplifier]
Input offset voltage
V
IO(FG)
10
+10
mV
Input bias current
I
B(FG)
1
+1
A
Output high-level voltage
V
OH(FG)
I
FGO
= 0.2 mA
V
REG
1.2
V
REG
0.8
V
Output low-level voltage
V
OL(FG)
I
FGO
= 0.2 mA
0.8
1.2
V
FG input sensitivity
Gain times 100
3
mV
Schmitt sensitivity for the next stage
Design target value
100
180
250
mV
Operating frequency range
2
kHz
Open loop gain
f
(FG)
= 2 kHz
45
51
dB
[Speed Discriminator]
Output high-level voltage
V
OH(D)
I
DO
= 0.1 mA
V
REG
1.0
V
REG
0.7
V
Output low-level voltage
V
OL(D)
I
DO
= 0.1 mA
0.8
1.1
V
Number of counts
512
[PLL Output]
Output high-level voltage
V
OH(P)
I
PO
= 0.1 mA
V
REG
1.8
V
REG
1.5
V
REG
1.2
V
Output low-level voltage
V
OL(P)
I
PO
= 0.1 mA
1.2
1.5
1.8
V
[Lock Detector]
Output low-level voltage
V
OL(LD)
I
LD
= 10 mA
0.15
0.5
V
Lock range
6.25
%
[Integrator]
Input bias current
I
B(INT)
0.4
+0.4
A
Output high-level voltage
V
OH(INT)
I
INTO
= 0.2 mA
V
REG
1.2
V
REG
0.8
V
Output low-level voltage
V
OL(INT)
I
INTO
= 0.2 mA
0.8
1.2
V
Open-loop gain
f (INT) = 1 kHz
45
51
dB
Gain-bandwidth product
Design target value
450
kHz
Reference voltage
Design target value
5%
V
REG
/2
5%
V
[Crystal Oscillator]
Operating frequency range
f
OSC
1
10
MHz
Low-level pin voltage
V
OSCL
I
OSC
= 0.5 mA
1.7
V
High-level pin current
I
OSCH
V
OSC
= V
OSCL
+0.3 V
0.5
mA
[Start/Stop Pin]
High-level input voltage range
V
IH(S/S)
3.5
V
REG
V
Low-level input voltage range
V
IL(S/S)
0
1.5
V
Input open voltage
V
IO(S/S)
V
REG
0.5
V
REG
V
Hysteresis
V
IN
0.35
0.50
0.65
V
High-level input current
I
IH(S/S)
V
(S/S)
= V
REG
10
0
+10
A
Low-level input current
I
IL(S/S)
V
(S/S)
= 0 V
280
210
A
[Forward/Reverse Pin]
Output high-level voltage
V
IH(F/R)
3.5
V
REG
V
Output low-level voltage
V
IL(F/R)
0
1.5
V
Input open voltage
V
IO(F/R)
V
REG
0.5
V
REG
V
Hysteresis
V
IN
0.35
0.50
0.65
V
Output high-level voltage
I
IH(F/R)
V
(F/R)
= V
REG
10
0
+10
A
Output low-level voltage
I
IL(F/R)
V
(F/R)
= 0 V
280
210
A
Continued from preceding page.
No. 5687-4/11
LB1924
Pin Assignment
Truth Table
Source
F/R = L
F / R = H
Sink
IN 1
IN2
IN 3
IN 1
IN 2
IN 3
1
OUT2
OUT1
H
L
H
L
H
L
2
OUT3
OUT1
H
L
L
L
H
H
3
OUT3
OUT2
H
H
L
L
L
H
4
OUT1
OUT2
L
H
L
H
L
H
5
OUT1
OUT3
L
H
H
H
L
L
6
OUT2
OUT3
L
L
H
H
H
L
Ambient temperature, Ta C
Allowable power dissipation, Pdmax W
Independent IC
With an arbitrarily large heat sink
Equivalent Circuit Block Diagram
No. 5687-5/11
LB1924
Functional Description
1. Speed control circuit
This IC uses a speed discriminator circuit and a PLL circuit in combination for speed control. The speed control
circuit outputs an error signal once every two FG periods (a charge pump technique). The PLL circuit outputs a phase
error signal once every FG period (also a charge pump technique). As compared with the earlier speed control
technique of using only a speed discriminator, the combined speed discriminator/PLL circuit technique is better able
to suppress speed fluctuations when used with motors with large load variations. The FG servo frequency is
determined by the following equation, which means that the motor speed is determined by the number of FG pulses
and the crystal oscillator frequency.
f
FG
(servo) = f
OSC
/8192
f
OSC
: Crystal oscillator frequency
2. Output drive circuit
This IC adopts a direct PWM drive technique to minimize the power loss in the output. The output transistor is
always saturated when on, and the motor drive power is adjusted by varying the duty with which the output is on.
Since the lower side output transistor is used for output switching, a Schottky diode or similar device must be
connected between OUT and V
CC
. (This is because a through current will flow at the instant the lower side transistor
turns on unless a diode with a short reverse recovery time is used.) The diode between OUT and ground is included
on chip in this device. If this becomes a problem for large output currents, (e.g. if the output waveform is disturbed
during lower side kickback) attach an external rectifying (or Schottky) diode.
3. Current limiter
The current limiter circuit limits the output to a current determined by the equation I = V
RF
/R
f
, where V
RF
= 0.5 V
(typical) and R
f
is the current detection resistor. The current limiting operation consists of reducing the output on duty
to lower the current.
4. Reference clock
Either of the two following input methods can be used for the speed control clock
Using a crystal oscillator element
-- When using a crystal oscillator element, connect the crystal, capacitors, and resistors as shown in the figure below
to form an oscillator circuit.
No. 5687-6/11
LB1924
Oscillator frequency (MHz)
C1 (F)
C2 (F)
C3 (F)
R1 (
)
R2 (
)
1 to 3
0.1
47
220
220 K
--
3 to 5
0.1
18
100
100 K
--
5 to 7
0.1
--
47
47 K
--
7 to 10
0.1
--
33
10 K
4.7 K
Sample External Circuit Constants (Reference values)
C1, R1: Oscillator stabilization
C3:
Oscillator coupling
C2:
Overtone prevention
R2:
Oscillator operating margin improvement
This circuit and these circuit constant values are provided for reference only. Always verify application circuits
with the supplier of the oscillator element to assure that the effects of the characteristics of the oscillator element
itself, the printed circuit board wiring, floating capacitances, and other aspects are accounted for appropriately.
(Notes on printed circuit board lines)
Floating capacitances on the printed circuit board can easily affect crystal oscillator circuits, since these are high-
speed circuits. The printed circuit board lines connecting these components should be kept as short and as narrow
as possible and other measures to reduce floating capacitances should be considered as well.
In this external circuit, the line between the oscillator element and C3 (C2) is particularly subject to floating
capacitance problems and requires special care.
V
REG
External clock (A frequency equivalent to the crystal oscillator frequency: 1 to 10 MHz)
-- If a frequency equivalent to a crystal oscillator frequency is input from an external source, input that signal through
a series resistor of about 13 k
to the XI pin. The XO pin should be left open.
Input signal levels:
Low-level voltage: 0 to 0.8 V
High-level voltage: 2.5 to 5.0 V
5. Speed lock range
The speed lock range is 6.25% of the set speed. When the motor speed is in the lock range the LD pin will go low
(open collector output). The IC controls the motor speed by changing the motor drive output on duty according to the
speed error signal if the motor speed goes outside the lock range.
6. PWM frequency
The PWM frequency is determined by the capacitor and resistor connected to the CR pin.
f
PWM
1/(0.5
C
R)
A PWM frequency in the range 15 to 25 kHz is desirable. If the PWM frequency is too low, the motor may resonate
at the PWM frequency when locked resulting in noise, since that frequency will be in the audible range. If the PWM
frequency is too high, the switching loss in the output transistor will increase. The value of the resistor must be over 5
k
.
7. Hall input signals
The signals input as the Hall inputs must have amplitudes that exceed the hysteresis, which has a maximum value of
24 mV. Considering noise, inputs with amplitudes of at least 100 mV are desirable. Attach a noise rejection capacitor
(around 0.001 to 0.01 F) across the IN3 Hall input (pins 26 and 27). Since these pins are adjacent to the OUT1
output pin, noise in this input may cause disturbances in the output waveforms.
8. F/R switching
The F/R pin can be used to change the direction of motor rotation. However the following points must be observed
when designing applications that will change the motor direction while the motor is turning.
Application circuit must be designed to handle the through current that occurs when the direction is switched.
However, increases in the V
CC
voltage during switching due to motor current flowing into the power supply system
instantaneously, must not exceed the rated voltage (30 V) of the device. Increase the value of the capacitor between
power supply and ground if this is a problem.
If the motor current after switching exceeds the current limiter upper limit, the lower side transistor will be turned
off. However, the high side transistor will go to the short braking state, and a current determined by the motor reverse
voltage and the coil resistance will flow in this transistor. Applications must be designed so that this current does not
exceed the rated current, 3.1 A. In general, switching the direction with the F/R pin at high motor speeds is
dangerous.
9. Lock protection circuit
This IC includes a built-in lock protection circuit to protect the IC and the motor when the motor is locked. In the
start state, if the LD output remains high for a fixed period (the unlocked state), the lower side transistor is turned off.
The capacitance of the capacitor connected to the CROCK pin sets this time. A time of a few seconds can be set with
a capacitance under 0.1 F.
Set time (seconds)
52
C (F)
To release the lock protection state, the IC must be set to the stopped state or the power must be turned off and
reapplied. The CROCK pin must be connected to ground if the lock protection circuit is not used.
10. Power supply stabilization
The large currents drawn by this IC can adversely affect the power supply voltage. Therefore a capacitor with a
sufficiently large value must be inserted between the V
CC
pin and ground. If a diode is inserted in the power supply
line to protect against destruction due to accidentally connecting the power supply with the polarity reversed, the
power supply line voltage will be even more easily affected and an even larger capacitor will be required.
No. 5687-7/11
LB1924
No. 5687-8/11
LB1924
Pin Functions
Pin No.
Pin
Pin function
Equivalent circuit
28
1
2
OUT1
OUT2
OUT3
Motor drive outputs
Connect Schottky diodes between these outputs and V
CC
.
3
GND2
Output block ground
4
V
CC
Power supply (blocks other than the output block)
6
V
REG
Regulated power supply output (5-V output)
Insert a capacitor (about 0.1 F) between this pin and ground
for regulation.
7
F/R
Forward/reverse control
Low: 0 to 1.5 V
High: 3.5 to V
REG
The open state functions as a high-level input.
Has a hysteresis of about 0.5 V.
Low: Forward
High or open: Reverse
8
S/S
Start/stop control
Low: 0 to 1.5 V
High: 3.5 to V
REG
The open state functions as a high-level input.
Has a hysteresis of about 0.5 V.
Low: Start
High or open: Stop
5
V
M
Output block power supply and output current detection.
Connect a resistor (R
f
) with a small resistance between this
pin and V
CC
.
The output current is limited to a current set according to the
equation I
OUT
= V
RF
/R
f
.
Continued on next page.
No. 5687-9/11
LB1924
Continued from preceding page.
Pin No.
Pin
Pin function
Equivalent circuit
9
10
XO
XI
Crystal oscillator connection.
The reference clock signal is generated by connecting a
crystal oscillator element to these pins.
If an external clock (with a frequency of a few MHz) is used,
connect that signal to the XI pin through a series resistor of
about 13 k
, and leave the XO pin open.
11
INT
OUT
Integrator amplifier output (speed control output)
12
INT
IN
Integrator amplifier input
13
P
OUT
PLL circuit output
Continued on next page.
PWM comparator
No. 5687-10/11
LB1924
Continued from preceding page.
Pin No.
Pin
Pin function
Equivalent circuit
14
D
OUT
Speed discriminator output.
High: Acceleration
Low: Deceleration
15
LD
Speed lock detection output
Outputs a low level when the motor speed is in the lock range
(6.25%).
16
FG
OUT
FG amplifier output
17
FG
IN
FG amplifier input
18
FG
IN
+
FG amplifier input (bias input).
The logic block initial reset is applied by connecting a
capacitor (of about 0.1 F) between FG
IN
+ and ground.
19
CROCK
Setting for the lock protection circuit operating time.
An operating time of about 2.5 seconds can be set by
connecting a capacitor of about 0.047 F between the
CROCK pin and ground.
Continued on next page.
FG Schmitt comparator
FG reset circuit
This catalog provides information as of July, 1999. Specifications and information herein are subject to
change without notice.
Specifications of any and all SANYO products described or contained herein stipulate the performance,
characteristics, and functions of the described products in the independent state, and are not guarantees
of the performance, characteristics, and functions of the described products as mounted in the customer's
products or equipment. To verify symptoms and states that cannot be evaluated in an independent device,
the customer should always evaluate and test devices mounted in the customer's products or equipment.
SANYO Electric Co., Ltd. strives to supply high-quality high-reliability products. However, any and all
semiconductor products fail with some probability. It is possible that these probabilistic failures could
give rise to accidents or events that could endanger human lives, that could give rise to smoke or fire,
or that could cause damage to other property. When designing equipment, adopt safety measures so
that these kinds of accidents or events cannot occur. Such measures include but are not limited to protective
circuits and error prevention circuits for safe design, redundant design, and structural design.
In the event that any or all SANYO products (including technical data, services) described or contained
herein are controlled under any of applicable local export control laws and regulations, such products must
not be exported without obtaining the export license from the authorities concerned in accordance with the
above law.
No part of this publication may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying and recording, or any information storage or retrieval system,
or otherwise, without the prior written permission of SANYO Electric Co., Ltd.
Any and all information described or contained herein are subject to change without notice due to
product/technology improvement, etc. When designing equipment, refer to the "Delivery Specification"
for the SANYO product that you intend to use.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not
guaranteed for volume production. SANYO believes information herein is accurate and reliable, but
no guarantees are made or implied regarding its use or any infringements of intellectual property rights
or other rights of third parties.
PS No. 5687-11/11
LB1924
Continued from preceding page.
Pin No.
Pin
Pin function
Equivalent circuit
20
CR
PWM oscillator frequency setting.
Connect a resistor (R) between this pin and V
REG
and a
capacitor (C) between this pin and ground. Values of R = 22
k
, and C = 4700 pF set a frequency of about 19 kHz.
21
GND1
Ground (blocks other than the output block)
22
23
24
25
26
27
IN1
+
IN1
IN2
+
IN2
IN3
+
IN3
Hall inputs
An input with IN
+
> IN
is taken to be a high level, and the
opposite state is taken to be a low level. Hall signals with
amplitudes greater that 100 mVp-p (differential) are desirable.
If noise on the Hall signals is a problem, connect capacitors
between the IN
+
and IN
pins.
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