Office Automation-Use 3-Phase Brushless Motor
Driver
Overview
The LB1820 is a three-phase brushless motor with a digital
speed control circuit built in.
The LB1820 is ideally suited for use in office automation
applications such as laser beam printers and drum motor
drivers.
Features
.
Three-phase brushless motor driver with digital speed control
function
.
30 V withstand voltage and 2.5 A output current
.
Current limiter built in
.
Low-voltage protection circuit built in
.
Thermal shutdown circuit built in
.
Hall amp with hysteresis
.
Start/stop pin built in
.
Crystal oscillator and divider built in
.
Digital speed control circuit built in
.
Lock detector built in
Package Dimensions
unit : mm
3147-DIP28HS
[LB1820]
SANYO : DIP28HS
Specifications
Absolute Maximum Ratings
at Ta = 25 C
Parameter
Symbol
Conditions
Ratings
Unit
Maximum supply voltage 1
V
CC
30
V
Maximum supply voltage 2
V
M
30
V
Output current
I
O
t
%
100 ms
2.5
A
Allowable power dissipation 1
Pd max 1
Independent IC
3
W
Allowable power dissipation 2
Pd max 2
With arbitrarily large heat sink
20
W
Operating temperature
Topr
20 to +80
C
Storage temperature
Tstg
55 to +150
C
Allowable Operating Ranges
at Ta = 25 C
Parameter
Symbol
Conditions
Ratings
Unit
Supply voltage range 1
V
CC
9.5 to 28
V
Supply voltage range 2
V
M
5 to 28
V
Voltage regulator output current
I
VH
0 to +20
mA
Comparator output current
I
OSC
0 to +30
mA
Lock detector output current
I
LD
0 to +20
mA
Ordering number: EN3302A
Monolithic Digital IC
LB1820
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
43096HA(II)/3260TA, TS(GTPS) No.3302-1/7
Electrical Characteristics
at Ta = 25 C, V
CC
= V
M
= 24 V
Parameter
Symbol
Conditions
min
typ
max
Unit
Supply current 1
I
CC1
33
50
mA
Supply current 2
I
CC2
Stop mode
3
5
mA
Output saturation voltage
V
O (sat)
1
I
O
= 1 A
2.1
3.0
V
V
O(sat)
2
I
O
= 2 A
3.0
4.2
V
Output leak current
I
O
leak
100
A
Voltage regulator
Output voltage
V
H
I
VH
= 10 mA
3.8
4.15
4.5
V
Voltage variation
V
H
1
V
CC
= 9.5 to 28 V
60
150
mV
Load variation
V
H
2
I
VH
= 5 to 20 mA
60
150
mV
Temperature coefficient
2
mV/ C
Hall amp
Input bias current
I
HB
1
4
A
Common-mode input voltage
V
ICM
1.5
2.8
V
Hall input sensitivity
100
mVp-p
Hysteresis width
V
IN
24
33
42
mV
Low-to-high input voltage
V
SLH
8
20
32
mV
High-to-low input voltage
V
SHL
25
13
1
mV
Oscillator
High-level output voltage
V
OH(CR)
2.9
3.2
3.5
V
Low-level output voltage
V
OL(CR)
0.9
1.1
1.3
V
Oscillation amplitude
1.8
2.1
2.4
V
Oscillation frequency
f
R = 30 k
, C = 1500 pF
18.5
kHz
Temperature coefficient
f
0.1
%/ C
Comparator output voltage
V
OSC
I
OSC
= 20 mA
1.5
V
Current limiter
Limiter 1
V
Rf
1
0.42
0.5
0.6
V
Limiter 2
V
Rf
2
0.4
0.44
0.48
V
Thermal shutdown
Thermal shutdown
temperature
TSD
Design target
150
180
C
Hysteresis width
TSD
30
C
Low-voltage protection voltage
V
LVSD
7.5
8.1
8.7
V
Hysteresis width
V
LVSD
0.45
0.6
0.75
V
FG amp
Input offset voltage
V
IO(FG)
10
+10
mV
Input bias current
I
B(FG)
1
+1
A
High-level output voltage
V
OH(FG)
I
FG
= 2 mA
5.6
6.2
6.8
V
Low-level output voltage
V
OL(FG)
I
(FG)
= 2 mA
1
1.5
V
FG input sensitivity
10
Gain
5
mV
Schmitt width at next stage
16
mV
Operating frequency range
5
kHz
Open-loop voltage gain
60
dB
Speed discriminator
High-level output voltage
V
OH(D)
4.7
V
Low-level output voltage
V
OL(D)
0.3
V
Maximum clock frequency
1.0
MHz
Number of counts
2044
2046
2048
Integrator
Input offset voltage
V
IO(INT)
10
+10
mV
Input bias current
I
B(INT)
0.4
+0.4
A
High-level output voltage
V
OH(INT)
3.7
4.3
4.9
V
Low-level output voltage
V
OL(INT)
0.8
1.2
V
Open-loop gain
60
dB
Gain-bandwidth product
1.6
MHz
Reference voltage
5%
V5/2
5%
V
5 V supply
V5
4.6
5
5.4
V
Continued on next page.
LB1820
No.3302-2/7
Continued from preceding page.
Parameter
Symbol
Conditions
min
typ
max
Unit
Lock detector
Low-level output voltage
V
OL(LD)
I
LD
=10 mA
0.5
V
Lock range
3.125
%
Start/stop pin
Start/stop operating voltage
0.4
0.5
0.6
V
Crystal Oscillator
Precision of oscillating
frequency
Referenced to indicated frequency
500
+500
ppm
Temperature coefficient
3
ppm/ C
Drift in rotational speed
0.01
%
Truth Table
Source
Sink
Input
IN1
IN2
IN3
1
OUT 3
OUT 2
H
H
L
2
OUT 3
OUT 1
H
L
L
3
OUT 2
OUT 1
H
L
H
4
OUT 2
OUT 3
L
L
H
5
OUT 1
OUT 3
L
H
H
6
OUT 1
OUT 2
L
H
L
Pin Assignment
Top view
With arbitrarily large
heat sink
Without heat sink
Allowable
power
dissipation,
Pd
max
W
Ambient temperature, Ta C
LB1820
No.3302-3/7
Internal Equivalent Circuit Block Diagram
LB1820
No.3302-4/7
Pin Description
Pin No.
Pin Name
Functions
19, 20
17, 18
15, 16
IN
+
1, IN
1
IN
+
2, IN
2
IN
+
3, IN
3
OUT 1: Hall element input pins for Phase 1. ``H'' logic is the state when IN
+
> IN
-
.
OUT 2: Hall element input pins for Phase 2. ``H'' logic is the state when IN
+
> IN
-
.
OUT 3: Hall element input pins for Phase 3. ``H'' logic is the state when IN
+
> IN
.
6
8
10
OUT 1
OUT 2
OUT 3
Output pin 1.
Output pin 2.
Output pin 3.
2
V
CC
Power supply for other than output blocks.
12
V
M
Power supply for output blocks.
11
R
f
Output current detection pin. R
f
is connected across this pin and GND to detect the output current as
voltage.
14
GND
Ground for other than output blocks.
The lowest potential of output transistor is the voltage at R
f
pin.
3
CR
Sets the oscillating frequency of the switching regulator.
1
OSC
Outputs duty-controlled pulses.
Open-collector output.
24
INT
OUT
Integrator output pin (speed control pin).
Varies the switching regulator output voltage.
25
INT
IN
Integrator input pin.
23
D
OUT
Speed discriminator output pin.
Goes LOW when the specified speed is exceeded.
4
C
Suppresses ripples in the motor current during operation of current limiter 2.
22
LD
Lock detection pin.
Goes HIGH when the motor rotation speed is within the locking range.
27
26
FG
IN
FG
IN
+
FG pulse input (Start/Stop control) pin.
FG pulse input (4 V supply) pin.
28
FG
OUT
FG amp output pin.
21
Xtal
Crystal oscillator connecting pin.
13
5 V
5 V supply pin.
LB1820
No.3302-5/7
Operation Notes
Speed Control Circuit
This IC uses a speed discrimination circuit to perform speed control. The rotation accuracy of the speed discrimination method
depends on the counter count. The counter count in this IC is 2046. On the FG1 cycle, a speed error signal with a resolution of
1/2046 is output from the D
OUT
pin (charge pump method).
The D
OUT
output shifts among three states: high, high impedance, and low:
High
: Output S (acceleration signal)
High impedance
: When neither output S nor output F is output
Low
: Output F (deceleration signal)
The relationship between the FG frequency (f
FG
) and the quartz oscillation frequency (f
OSC
) can be calculated as follows:
f
FG
= f
OSC
(ECL division ratio
count)
f
OSC
(8
2046)
f
OSC
16368
PAM Drive System
This IC controls motor rotations by configuring an external switching regulator, and controlling the voltage (V
M
) of the regulator.
Select a switching regulator diode with a short reverse recovery time such as an FRD (First Recovery Diode). Because even a
smooth coil can become a noise source, attention must be paid to the arrangement of components on the board (especially
avoiding the effects of FG signal lines and integrated amplifiers).
Select a normal rectifier diode for the upper and lower motor drive pin section (OUT1 to 3).
Current Limiter Circuit
The current limiter circuit consists of two limiter circuits.
1 Limiter 1
Detection voltage V
Rf
1 = 0.5 V typ. Current is limited by putting the lower output transistor in the nonsaturated state and
then dropping the voltage applied to the motor.
2 Limiter 2
Detection voltage V
Rf
2 = 0.44 V typ. The V
M
voltage is limited by limiting the OSC pin ``on duty'' ratio.
Normally, if an excessive load is put on the motor, limiter 1 operates first, and after a delay in the switching regulator, limiter 2
operates.
Sometimes, after startup, the ASO of the output transistor is very severe. In such a case, it is necessary to perform a soft start (in
which V
M
is increased gradually). When using soft starts, connect a capacitor between the pin (V
M
, 5 V, etc.) on which the
voltage is to be increased during startup and the C pin. If soft starts are not to be used, connect a capacitor between the C pin and
ground.
Speed Lock Range
The speed lock signal is output from the LD pin. The speed lock range is within 3.13%; if the motor rotations fall within the
lock range the LD pin goes low (open collector output).
Start/stop Operation
The FG
IN
-
pin also serves as the start/stop pin. When the FG
IN
-
pin is connected to a transistor, etc., and the voltage is 0.5 V typ.
or less, the stop state goes into effect. In the stopped state, in addition to the drive outputs being turned off, the FG
IN
+
, 5 V, and
other regulator outputs are also turned off.
When it is necessary to drive the motor at high speed, improvement is possible by adding a resistor (of approximately 1 M
)
between FG
OUT
and V
CC
. (The time from when the transistor is turned off until FG
IN
-
goes to 0.5V is reduced.)
Initial Reset Operation
At startup, it is possible to apply an initial reset to the logic circuits by delaying the increase in voltage on FG
IN
-
. If an initial
reset is not applied, the LD pin may go low from start until the FG pulse is input to the logic circuits (until output of
approximately 16 mVp-p is generated on FG
OUT
).
When an FG reset is applied, the capacitor between the FG
IN
+
and GND should be 4.7 F or more (in order to delay the rise in
FG
IN
-
). Caution is required, because if the FG amplifier input capacitor is too small and the feedback capacitor is too large, the
reset time will be shorter. At start, a delay of about 5 s or more from the rising edge of the 5 V regulator output until the FG
IN
-
voltage goes to 1.2 V is desirable.
LB1820
No.3302-6/7
PWM Frequency Setting
The PWM frequency is determined by the resistor and capacitor connected to the CR pin. When a resistor is connected to the
FG
IN+
pin, the PWM frequency can be roughly calculated by the following formula:
f
PWM
6 1
(1.2
C
R)
The resistor must not be less than 30 k
. It is desirable for the PWM frequency to be about 15 kHz.
Quartz Oscillator
An oscillator, capacitor and resistor are to be connected to the quartz oscillator. When selecting the oscillator and the external
capacitor and resistor, always obtain approval from the manufacturer of the oscillator in order to avoid problems.
(Circuit with external quartz oscillator)
External constants (reference values)
Xtal (MHz)
C1 (pF)
C2 (pF)
R (k
)
3 to 4
39
82
0.82
4 to 5
39
82
1.0
5 to 7
39
47
1.5
7 to 10
39
27
2.0
However, use a crystal such that the base wave
f
O
impedance : 3f
O
impedance = 1 : 5 or more
When inputting external signals (of several MHz) to the quartz oscillator, connect external components as shown in the diagram
below.
f
IN
= 1 to 8 MHz
Input signal level High level voltage: 4.0 V min.
Low level voltage: 1.5 V max.
Ra = 2 k
, Rb = 1 k
(reference values)
No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment,
nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or
indirectly cause injury, death or property loss.
Anyone purchasing any products described or contained herein for an above-mentioned use shall:
1
Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors
and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and
expenses associated with such use:
2
Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO
ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally.
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.
This catalog provides information as of April, 1996. Specifications and information herein are subject to change without notice.
5 V pin
Xtal pin
Input
LB1820
No.3302-7/7
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