SANYO LB8502M

Ordering number : EN8337
Monolithic Digital IC
DC Fan Motor Speed
Control IC
LB8502M
Overview
The LB8502M easily and simply implements feedback-based motor speed control in combination with a general-purpose
motor driver IC.
Compared to open-loop control, the use of speed feedback allows the motor speed precision to be improved and the speed
fluctuations due to load variations to be minimized.
• LB8502M: For use as a driver IC that increases the motor speed as the command voltage rises (three-phase systems)
Features
• Achieves linear speed control
Applications can set the slope of the change in motor speed with change in the input duty.
• Minimized speed fluctuations in the presence of line or load variations
• Allows a minimum speed to be set
• Soft start function
• Settings using external capacitors and resistors (to support easier mass production of end products)
• Supports both PWM duty and analog voltage control inputs
Specifications
Absolute Maximum Ratings at Ta = 25°C
Parameter
Symbol
Conditions
Supply voltage
VCC max
VCC pin
Output current
IO max
E0 pin
Allowable power dissipation
Pd max
When mounted on a circuit board *1
Ratings
Unit
18
V
3
mA
0.87
W
Operating temperature
Topr
-30 to +95
°C
Storage temperature
Tstg
-55 to +150
°C
*1 Specified circuit board : 114.3 × 76.1 × 1.6mm3, glass epoxy.
Any and all SANYO Semiconductor Co.,Ltd. products described or contained herein are, with regard to
"standard application", intended for the use as general electronics equipment (home appliances, AV equipment,
communication device, office equipment, industrial equipment etc.). The products mentioned herein shall not be
intended for use for any "special application" (medical equipment whose purpose is to sustain life, aerospace
instrument, nuclear control device, burning appliances, transportation machine, traffic signal system, safety
equipment etc.) that shall require extremely high level of reliability and can directly threaten human lives in case
of failure or malfunction of the product or may cause harm to human bodies, nor shall they grant any guarantee
thereof. If you should intend to use our products for applications outside the standard applications of our
customer who is considering such use and/or outside the scope of our intended standard applications, please
consult with us prior to the intended use. If there is no consultation or inquiry before the intended use, our
customer shall be solely responsible for the use.
Specifications of any and all SANYO Semiconductor Co.,Ltd. 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.
32807 TI PC B8-8968 No.8337-1/11
LB8502M
Allowable Operating Ranges at Ta = 25°C
Parameter
Symbol
Conditions
Ratings
Unit
Supply voltage range 1
VCC1
VCC pin
7.5 to 17
Supply voltage range 2
VCC2
VCC pin, with VCC shorted to
6VREG
5.5 to 6.5
Output current
IO
V
2.5
mA
IREG
-5
mA
CTL pin voltage
VCTL
0 to VREG
V
LIM pin voltage
VLIM
0 to VREG
V
6V constant voltage output
E0 pin
V
current
Electrical Characteristics at Ta = 25°C, VCC = 12V
Parameter
Symbol
Ratings
Conditions
min
Supply current
Unit
typ
ICC
max
4.5
6.5
mA
6V constant voltage output (VREG pin)
Output voltage
VREG
6.0
6.2
V
Line regulation
∆VREG1
VCC = 8 to 17V
5.8
40
100
mV
Load regulation
∆VREG2
IO = 0 to 5mA
50
100
Temperature coefficient
∆VREG3
Design target*
0
mV
mV/°C
Integrating Amplifier Block
Common-mode input voltage
VICM
0
VREG- 2.0
V
1.0
V
range
High-level output voltage
VOH
IEO = -0.2mA
Low-level output voltage
VOL
IEO = 0.2mA
VREG - 1.2
V
VREG - 0.8
0.8
FGIN pin
High-level input voltage
VFGH
3.0
VREG
V
Low-level input voltage
VFGL
0
1.5
V
Input open voltage
VFGO
VREG - 0.5
VREG
V
Hysteresis
VFGS
High-level input current
IFGH
VFGIN = 6VREG
Low-level input current
IFGL
VFGIN = 0V
0.2
0.25
0.4
V
-10
0
10
µA
-140
-110
µA
RC pin
High-level output voltage
VOH(RC)
3.2
3.45
3.7
V
Low-level output voltage
VOL(RC)
0.8
0.95
1.05
V
Clamp voltage
VCLP(RC)
1.6
V
CTL pin
High-level input voltage
VCTH
2.0
VREG
V
Low-level input voltage
VCTL
0
1.0
V
Input open voltage
VCTO
VREG - 0.5
VREG
V
High-level input current
ICTH
VFGIN = 6VREG
10
µA
Low-level input current
ICTL
VFGIN = 0V
-10
0
-140
-110
µA
C pin
High-level input voltage
VOH(C)
3.8
4.0
4.2
V
Low-level input voltage
VOL(C)
0.05
0.1
0.2
V
IB(LIM)
-1
0
µA
VILIM
0
VREG- 2.0
V
LIM pin
Input bias current
Common-mode input voltage
range
*The design specification items are design guarantees and are not measured.
No.8337-2/11
LB8502M
Package Dimensions
unit : mm (typ)
3086B
5
6.4
1
0.15
0.1 (1.5)
1.7max
4.4
6
0.63
5.0
10
0.35
(0.5)
1.0
SANYO : MFP10S(225mil)
Pin Assignment
EO
EI
GND
LIM
FGIN
10
9
8
7
6
LB8502M
1
2
3
4
5
RC
VREG
VCC
C
CTL
Top view
Pin Functions
Pin
Pin No.
Description
1
RC
One-shot multivibrator pulse width setting. Connect a resistor between this pin and VREG, and a capacitor between this
2
VREG
3
VCC
4
C
pin and ground.
6V regulator output. Connect a capacitor between this pin and ground for stabilization.
Power supply. Connect a capacitor between this pin and ground for stabilization.
Duty pulse signal smoothing and soft start time setting. Connect a capacitor between this pin and VREG.
5
CTL
Duty pulse signal input. The speed is controlled by the duty of this pulse signal.
6
FGIN
FG pulse input
7
LIM
8
GND
9
EI
10
EO
Minimum speed setting. Normally, the 6V regulator level is resistor divided to set this pin's input level.
Ground pin
One-shot multivibrator output and integrating amplifier input. A capacitor must be connected between this pin and EO for
this integration.
Integrating amplifier output.
No.8337-3/11
LB8502M
Block Diagrams and Application Examples
When the FG signal
is output to another
circuit board
Driver IC
12V
VCC
LB8502M
VREG
6VREG
C4
6VREG
FGIN
C5
EDGE
R3
FG
FGIN
One-shot
multivibrator
RC
EI
C3
R1
C2
LIM
EO
VCTL
R2
VREF
C
C1
CTL
signal
180kΩ
CTL
CTL
GND
No.8337-4/11
LB8502M
Speed Control Diagrams
The slope is determined by the external
constant connected to the RC pin.
(RPM)
For a smaller RC
time constant
For a larger RC
time constant
Speed
Minimum
speed
Determined by the LIM pin voltage
Low← CTL pin (PWM DUTY)
Low ←
EO pin voltage (V)
0%
Set minimum
speed
→High
→ High
Variable speed
Low on duty
(%)
(V)
Full speed
High on duty
CTL pin
6VREG
EO voltage
EO pin
LIM voltage
0V
Startup Timing (soft start)
VCC pin
CTL pin
EO pin
Stop
Stop
Full speed
Soft start
The slope can be changed with the capacitor
connected to the C pin (A larger capacitor increases
the slope.)
Full speed
No.8337-5/11
LB8502M
Supplementary Operational Descriptions
The LB8502M accepts a duty pulse input and an FG signal from the driver IC, and generates the driver IC control
voltage so that the FG period (motor speed) becomes proportional to the control voltage.
Driver IC
LB8502M
FGIN
CTL
signal
FG
CTL
Closed
feedback
loop
EO
VTH
As shown in the figure below, the LB8502M generates a pulse signal from edges on the FG signal and then generates a
pulse width waveform determined by the RC time constant in a one-shot multivibrator.
The LB8502M then integrates that pulse waveform to create the output driver IC control voltage (a DC voltage).
FG
EDGE pulse
Slope due to the
RC time constant
RC pin
One-shot
multivibrator
TRC(s) = 0.85RC
It is also possible to change the slope of the VCTL/speed relationship as shown in the speed control diagram in the
previous section by changing the pulse width with the RC time constant.
Note, however, that since pulses determined by this RC time constant are used, variation in the RC components will
appear as speed control errors.
No.8337-6/11
LB8502M
Pin Setting Procedures (Provided for reference purposes)
1. RC pin
The one-shot multivibrator pulse width can be calculated with the following equation.
TRC(s) ≈ 0.85 × R × C..................................................... Equation 1
If the FG signal frequency at full motor speed is fFG (Hz) and the control duty desired for full speed is DUTY (for
example: 50% → 0.5), the values of the resistor and capacitor connected to the RC pin can be determined from the
following equation.
R × C = DUTY/(3 × 0.85 × fFG) ..................................... Equation 2
Note that if "rpm" is the full motor speed, since one revolution will be two FG periods, the following equation gives the
FG frequency, fFG (Hz).
fFG(Hz) = 2rpm/60 ......................................................... Equation 3
For reference purposes, the following table lists the RC pin external component values determined from equations 2
and 3 when the control duty at full speed will be 80% for a variety of full motor speed values.
Note that the capacitor value must be in the range 0.01µF to 0.015µF due to the RC pin discharge capacity of the IC.
Full motor speed
R×C
R
C
10000rpm
0.94 × 10-3
63kΩ
0.015µF
8000rpm
1.18 × 10-3
78kΩ
0.015µF
6000rpm
1.57 × 10-3
105kΩ
0.015µF
4000rpm
2.39 × 10-3
157kΩ
0.015µF
2000rpm
4.68 × 10-3
312kΩ
0.015µF
The table below lists the RC pin external component values when the control duty for full motor speed is changed for a
full motor speed of 10,000rpm.
Duty at full speed
R×C
R
C
80% (= 0.8)
0.94 × 10-3
94kΩ
0.01µF
60% (= 0.6)
0.71 × 10-3
71kΩ
0.01µF
40% (= 0.4)
0.47 × 10-3
47kΩ
0.01µF
Also, note that the FG frequency can be determined from the following equation for various control duty input states.
fFG = DUTY/(3 × 0.85 × RC).......................................... Equation 4
2. C Pin
Since a capacitor that can smooth the pin voltage is connected to the C pin, if the CTL pin input signal frequency is f
(Hz), then the capacitor must meet the following condition. (Here, R is the IC internal resistance of 180kΩ (typical).)
1/f = t < RC
Note that the larger the capacitor, the longer the soft start time will be and its response to changes in the input signal will
be slower.
CTL pin
VREF circuit
CTL circuit
180kΩ
C pin
A capacitor that can smooth the pin voltage is connected
here.
1/f = t < CR
No.8337-7/11
LB8502M
3. LIM pin
The LIM pin external component values can be derived as follows for the case where a motor whose maximum speed
of 10,000rpm is to be achieved with an 80% duty, and a minimum speed of 3000rpm is to be set.
Ra = minimum speed/full speed = 3000/10,000 = 0.3
Full-speed duty × Ra = 0.8 × 0.3 = 0.24
LIM pin voltage = 4 × 0.24 ≈ 1V
From the above, the required LIM pin voltage is about 1V.
To generate this 1V level by resistor dividing the 6 V regulator level, the resistor ratio will be 5: 1, and the resistors
connected to the LIM pin will have the following values.
Between 6VREG and LIM pin : 50kΩ
Between LIM pin and GND : 10kΩ
(RPM)
12000
10000
8000
6000
4000
Minimum
speed
2000
0
0%
0V
20% 24%
1V
40%
60%
CTL Duty (PWM duty)
LIM pin voltage
80%
100%
4V
No.8337-8/11
LB8502M
Application Example 2
[Fixed Speed + Soft Start]
With this circuit, the motor speed remains constant even if there are fluctuations in the supply voltage or static voltage.
(RPM)
Motor
full speed
0%
20%
40%
60%
80%
CTL signal (PWM duty)
C pin voltage
0V
100%
4V
Driver IC
12V
VCC
LB8502M
VREG
6VREG
FGIN
EDGE
One-shot
multivibrator
RC
FG
FGIN
EI
LIM
EO
VCTL
VREF
C
180kΩ
CTL
CTL signal
CTL
GND
Input a fixed-duty signal to the CTL pin signal input as an input signal for which soft start is enabled at startup.
Alternatively, apply a constant voltage to the C pin. (In this case, the CTL pin must be left open.)
No.8337-9/11
LB8502M
Application Example 3
[Analog Input]
DC voltage speed control
(RPM)
Motor
full speed
Set minimum
speed
0
0V
0.8V
1.6V
2.4V
3.2V
4.0V
C pin voltage
Driver IC
12V
VCC
VREG
LB8502M
6VREG
FGIN
EDGE
FG
FGIN
One-shot
multivibrator
RC
EI
LIM
VCTL
signal
EO
VCTL
VREF
C
180kΩ
CTL
CTL
GND
No.8337-10/11
LB8502M
SANYO Semiconductor Co.,Ltd. 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 Semiconductor Co.,Ltd.
products described or contained herein.
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semiconductor products fail or malfunction with some probability. It is possible that these probabilistic failures or
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product/technology improvement, etc. When designing equipment, refer to the "Delivery Specification" for the
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Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed
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This catalog provides information as of March, 2007. Specifications and information herein are subject
to change without notice.
PS No.8337-11/11