Ordering number : ENN6087A

21003AS (OT) / 52199RM (KI) No. 6087-1/12

Overview

The LB1975 is a three-phase brushless motor driver IC
suited for use in direct PWM driving of DC fan motors for
air conditioners, water heaters, and other similar
equipment. Since a shunt regulator circuit is built in,
single power supply operation sharing the same power
supply for the motor is supported.

Features

· Withstand voltage 45 V, output current 2.5 A
· Direct PWM drive output
· 3 built-in output top-side diodes
· Built-in current limiter
· Built-in FG output circuit

Package Dimensions

unit: mm

3147C-DIP28H

0.4

0.6

4.0

26.75

20.0

R1.7

8.4

(1.81)

1.78

1.0

12.7

11.2

SANYO: DIP28H

[LB1975]

LB1975

SANYO Electric Co.,Ltd. Semiconductor Company

TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN

DC Fan Motor Driver

Monolithic Digital IC

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.

No. 6087-2/12

LB1975

Parameter

Symbol

Conditions

Ratings

Unit

Supply voltage

max

Output current

max

2.5

Maximum input current

REG

max

REG

Allowable power dissipation

Pd max1

IC only

Pd max2

With infinite heat sink

Operating temperature

Topr

20 to +100

°C

Storage temperature

Tstg

55 to +150

°C

Specifications

Absolute Maximum Ratings

at Ta = 25°C

Parameter

Symbol

Conditions

Ratings

Unit

Supply voltage range

4.5 to 6.7

20 to 42

Input current range

REG

1 to 5

FG pin applied voltage

0 to V

FG pin output current

0 to 10

Allowable Operating Ranges

at Ta = 25°C

100

120

Allowable power dissipation, Pd max

Pd max Ta

Ambient temperature, Ta °C

With infinite heat sink

Independent IC

No. 6087-3/12

LB1975

Parameter

Symbol

Conditions

Ratings

Unit

min

typ

max

Supply current

[Output Block]

sat1 (L) I

= 1.0 A, V

(sink)

1.1

1.4

sat1 (H) I

= 1.0 A, V

(source)

0.9

1.3

Output saturation voltage

sat1

= 1.0 A, V

(sink) + V

(source)

2.0

2.6

sat2 (L) I

= 2.0 A, V

(sink)

1.4

1.8

sat2 (H) I

= 2.0 A, V

(source)

1.2

1.7

sat2

= 2.0 A, V

(sink) + V

(source)

2.6

3.4

Output leak current

Leak (L)

100

µA

Leak (H)

100

µA

Upper side diode forward voltage

= 1.0 A

1.2

1.6

= 2.0 A

2.1

2.6

[Hall Amplifier]

Input bias current

µA

Common-mode input voltage range

ICM

1.5

Hall input sensitivity

mVp-p

Hysteresis width

(HA)

Input voltage (low to high)

SLH

Input voltage (high to low)

SHL

[FG Pin (speed pulse output)]

Output low-level voltage

FGL

= 5 mA

0.5

Pull-up resistor value

7.5

12.5

[Current Limiter]

Limiter

0.45

0.50

0.55

[Thermal Shutdown]

Thermal shutdown operating temperature

TSD

Desigh target Value (junction temperature)

150

180

°C

Hysteresis width

TSD

Desigh target Value (junction temperature)

°C

[Low-Voltage Protection]

Operating voltage

LVSD

3.5

3.8

4.1

Non-operating voltage

LVSD

(OFF)

4.3

4.5

Hysteresis width

LSD

0.4

0.5

0.6

[PWM Oscillator]

Output high-level voltage

(OSC)

2.95

3.10

3.25

Output low-level voltage

(OSC)

1.38

1.45

1.59

Amplitude

OSC

1.50

1.65

1.71

Vp-p

Ocillator frequency

OSC

C = 2200 pF

19.6

23.0

27.6

kHz

Charge current

CHG

110

µA

Discharge resistance

DCHG

1.6

2.1

2.6

REG

Pin]

Pin voltage

REG

= 1.5 mA

6.6

7.0

7.2

CTL

Pin]

Input voltage

CTL

Output duty 0%

1.1

1.4

1.7

CTL

Output duty 100%

3.2

3.5

3.8

Input bias current

1 (CTL)

CTL

= 0 V

µA

2 (CTL)

CTL

= 5 V

µA

CTL

Amplifier]

Reference voltage

CREF

2.23

2.35

2.46

Output voltage

COUT

CTL

= 0 V

3.90

4.20

4.40

COUT

CTL

= 5 V

0.60

0.80

1.10

[Start/Stop Pin]

High-level input voltage range

(S/S)

1.5

Low-level input voltage range

(S/S)

1.5

Input open voltage

(S/S)

0.5

Electrical Characteristics

at Ta = 25°C, V

= 5 V, V

= 30 V

Continued on next page.

No. 6087-4/12

LB1975

Parameter

Symbol

Conditions

Ratings

Unit

min

typ

max

Hysteresis width

(S/S)

0.35

0.50

0.65

High-level input current

(S/S)

V (S/S) = V

µA

Low-level input current

(S/S)

V (S/S) = 0 V

280

210

µA

[Forward/Reverse Pin]

High-level input voltage range

(F/R)

1.5

Low-level input voltage range

(F/R)

1.5

Input open voltage

(F/R)

0.5

Hysteresis width

(F/R)

0.35

0.50

0.65

High-level input current

(F/R)

V (F/R) = V

µA

Low-level input current

(F/R)

V (F/R) = 0 V

280

210

µA

Continued from preceding page.

LB1975

VCOUT

VCC VREG S/S

F/R

(NC) OUT1 OUT2 OUT3 (NC) (NC) GND3 GND2

VCTL OSC (NC) VCREF IN1

IN1

IN2

IN3

FG1

FG2 GND1

Top view

A11950

Pin Assignment

Truth Table

F/R

Forward rotation Low

0 V to 1.5 V

Reverse rotation High

1.5 V to V

FG output

Input

Forward/reverse control

Output

FG output

IN1

IN2

IN3

F/R

Source

Sink

FG1

FG2

OUT2

OUT1

OUT2

OUT3

OUT1

OUT3

OUT2

OUT3

OUT1

OUT2

OUT1

OUT3

OUT1

OUT2

OUT3

OUT2

FG1

FG2

No. 6087-6/12

LB1975

Pin Functions

Pin No.

Pin name

Pin voltage

Pin function

Equivalent circuit

Power supply for blocks other than
the output block

A11953

4.5 V to 6.7 V

Shunt regulator output pin (7 V)

REG

0.0 V to 7.3 V

A11954

VCC

20 k

3.8 k

Start/stop control pin

Low: start

High or Open: stop

Typical threshold voltage for
V

= 5 V:

approx. 2.8 V (low to high)

approx. 2.3 V (high to low)

S/S

0.0 V to V

A11955

VCC

20 k

3.8 k

Forward/reverse pin

Low: forward

High or Open: reverse

Typical threshold voltage for
V

= 5 V:

approx. 2.8 V (low to high)

approx. 2.3 V (high to low)

F/R

0.0 V to V

A11956

VCC

200

0.5 V

Output pin 1

Output pin 2

Output pin 3

Output current detect pin. Connect
resistor RF between this pin and
ground. Output current is limited to
value set with V

/Rf. (Current limiter

operation)

OUT1

OUT2

OUT3

0.0 V to V

Output block power supply

Output block ground

GND3

Continued on next page.

No. 6087-7/12

LB1975

Continued from preceding page.

Pin No.

Pin name

Pin voltage

Pin function

Equivalent circuit

Ground for blocks other than the
output block

A11957

16 17

VCC

10 k

GND1

GND2

Speed pulse output pin 1 with built-in
pull-up resistor

Speed pulse output pin 2 with built-in
pull-up resistor

FG1

FG2

0.0 V to V

A11958

VCC

300

Hall input pin

IN+ > IN : High input

IN+ < IN : Low input

IN1+

IN1

IN2+

IN2

IN3+

IN3

1.5 V to

1.5 V

A11959

VCC

2 V

200

2.1 k

This pin sets the PWM oscillation
frequency. Connect a capacitor
between this pin and ground.

OSC

1.0 V to V

A11960

VCC

2.35 V

31 k

40 k

Output duty cycle control pin

· V

CTL

Duty cycle 0%

· V

CTL

1 < V

CTL

< V

CTL

Duty cycle is controlled by V

CTL

· V

CTL

Duty cycle 100%

CTL

0.0 V to 6.7 V

Continued on next page.

IC Description

Direct PWM Drive

This IC (LB1975) employs the direct PWM drive principle. Motor rotation speed is controlled by varying the output
duty cycle according to an analog voltage input (V

CTL

). This eliminates the need to alter the motor power supply

voltage. Compared to previous ICs using the PAM principle (such as the Sanyo LB1690), this allows simplification of
the power supply circuitry. The V

CTL

input can be directly supplied by a microcontroller, motor speed can, therefore, be

controlled directly from the microcontroller.
For PWM, the source-side output transistors are switched on and off so that the ON duty tracks the V

CTL

input. The

output duty cycle can be controlled over the range of 0% to 100% by the V

CTL

input.

PWM Frequency

The PWM oscillator frequency f

PWM

[Hz] is set by the capacitance C [pF] connected between the OSC pin and GND.

The following equation applies:
f

PWM

1 / (1.97

Because output transistor on/off switching is subject to a delay, setting the PWM frequency to a very high value will
cause the delay to become noticeable. The PWM frequency therefore should normally be kept below 40 kHz (typ.),
which is achieved with a capacitance C of 1300 pF or higher. For reference, the source-side output transistor switching
delay time is about 2 µs for ON and about 4 µs for OFF.

Output Diodes

Because the PWM switching operation is carried out by the source-side output transistors, Schottky barrier diodes must
be connected between the OUT pins and GND (OUT1 to OUT3). Use diodes with an average forward current rating in
the range of 1.0 to 2.0 A, in accordance with the motor type and current limiting requirements.
If no Schottky barrier diodes are connected externally, or if Schottky barrier diodes with high forward voltage (V

) are

used, the internal parasitic diode between OUT and GND becomes active. When this happens, the output logic circuit
may malfunction, resulting in feedthrough current in the output which can destroy the output transistors. To prevent this
possibility, Schottky barrier diodes must be used and dimensioned properly.
The larger the V

of the externally connected Schottky barrier diodes, or the hotter the IC is, the more likely are the

parasitic diodes between OUT and GND to become active and the more likely is malfunction to occur. The V

of the

Schottky barrier diodes must be determined so that output malfunction does not occur also when the IC becomes hot. If
malfunction occurs, choose a Schottky barrier diode with lower V

Protection circuits

· Low voltage protection circuit

When the V

voltage falls below a stipulated level (V

LVSD

), the low voltage protection circuit cuts off the source-side

output transistors to prevent V

related malfunction.

· Thermal shutdown circuit (overheat protection circuit)

When the junction temperature rises above a stipulated value (TSD), the thermal shutdown circuit cuts off the source-
side output transistors to prevent IC damage due to overheating. Design the application heat characteristics so that the
protection circuit will not be triggered under normal circumstances.

· Current limiter

The current limiter cuts off the source-side output transistors when the output current reaches a preset value (limiter
value). This interrupts the source current and thereby limits the output current peak value. By connecting the
resistance Rf between the RF pin and ground, the output current can be detected as a voltage. When the RF pin voltage
reaches 0.5 V (typ.), the current limiter is activated. It performs on/off control of the source-side output transistors,
thereby limiting the output current to the value determined by 0.5 /Rf.

No. 6087-9/12

LB1975

Hall Input Circuit

The Hall input circuit is a differential amplifier with a hysteresis of 32 mV (typ.). The operation DC level must be within
the common-mode input voltage range (1.5V to V

1.5 V). To prevent noise and other adverse influences, the input

level should be at least 3 times the hysteresis (120 to 160 mVp-p). If noise at the Hall input is a problem, a noise-
canceling capacitor (about 0.01 µF) should be connected across the Hall input IN

and IN

pins.

FG Output Circuit

The Hall input signal at IN1, IN2, and IN3 is combined and subject to waveform shaping before being output. The signal
at FG1 has the same frequency as the FG1 Hall input, and the signal at FG2 has a frequency that is three times higher.

Start/Stop Control Circuit

The start/stop control circuit turns the source-side output transistors OFF (motor stop) when a High signal is input at the
S/S pin or when the pin is Open. When a Low signal is input at the S/S pin, the source-side output transistors are turned
ON, and the normal operation state is established (motor start).

Forward/Reverse Switching

This IC is designed under the assumption that forward/reverse switching is not carried out while the motor is running. If
switching is carried out while the motor is running, reverse torque braking occurs, leading to a high current flow. If the
current limiter is triggered, the source-side output transistors are switched off, and the sink-side output transistors go into
the short brake condition. However, because the current limiter of this IC cannot control the current flowing in the sink-
side output transistors, these may be destroyed by the short brake current. Therefore F/R switching while the motor is
running is permissible only if the output current (I

) is limited to a maximum of 2.5 A using the motor coil resistance or

other suitable means.
F/R switching should be carried out only while a High signal is input to the S/S pin or the pin is Open (stop condition), or
while the V

CTL

pin conforms to the following condition: V

CTL

1 (duty cycle 0%). In any other condition, F/R

switching will result in feedthrough current. The F/R pin should therefore be fixed to Low (forward) or High or Open
(reverse) during use.

, V

Power Supplies

When the power supply voltage (V

, V

) rises very quickly when a power is first applied, a feedthrough current may

occur at the output. If the current remains below about 0.2 A to 0.3 A, it does not pose a problem, but such a possibility
should still be prevented by slowing down the voltage rise at power-on. Especially if the F/R pin is set to High or Open
(reverse), a quick rise in V

is likely to cause feedthrough current. This should be prevented by ensuring that

= 0.2 V/µs or less. Feedthrough current can also be prevented by first switching on V

and then V

during power-on.

The sequence at power-down should be as follows. Provide a stop input to the S/S pin or a duty ratio 0% input to the
V

CTL

pin. When the motor has come to a full stop, switch off V

and then V

. If power is switched off while the

motor is still rotating or a current is flowing in the motor coil (including motor restraint or inertia rotation), a
counterelectromotive current or kickback current may flow on the V

side, depending on the motor type and power-off

procedure. If this current cannot be absorbed by the V

power supply or a capacitor, V

voltage may rise and exceed

the absolute maximum V

rating for the IC. Ensure that this does not happen through proper design of the V

power

supply or through use of a capacitor.
Because the IC (LB1975) incorporates a shunt regulator, it can be used on a single power supply. In this case, supply
V

(6.3 typ.) to the V

REG

pin via an external NPN transistor and resistor. When not using the regulator, leave the V

REG

pin open.

No. 6087-10/12

LB1975

Power Supply Stabilizing Capacitors

If the V

line fluctuates drastically, the low-voltage protection circuit may be activated by mistake, or other

malfunctions may occur. The V

line must therefore be stabilized by connecting a capacitor of at least several µF

between V

and GND. Because a large switching current flows in the V

line, wiring inductance and other factors can

lead to V

voltage fluctuations. As the GND line also fluctuates, the V

line must be stabilized by connecting a

capacitor of at least several µF between V

and GND, to prevent exceeding V

max or other problems. Especially when

long wiring runs (V

, V

, GND) are used, sufficient capacitance should be provided to ensure power supply stability.

CREF

Pin, V

COUT

These pins are always used in the Open condition. If chattering occurs in the PWM switching output, connect a capacitor
(about 0.1 µF) between V

CREF

and ground or between V

COUT

and GND.

IC Heat Dissipation Fins

A heat sink may be mounted to the heat dissipation fins of this IC, but it may not be connected to GND. The sink should
be electrically open.
Sample calculation for internal power dissipation (approximate)
The calculation assumes the following parameters:
V

= 5 V

= 30 V

Source-side output transistor ON duty cycle 80% (PWM control)
Output current I

= 1 A (RF pin average current)

· I

power dissipation P1

P1 = V

= 5 V

14 mA = 0.07 W

· Output drive current power dissipation P2

P2 = V

11 mA = 30 V

11 mA = 0.33 W

· Source-side output transistor power dissipation P3

P3 = V

(source)

Duty (on) = 0.9 V

1 A

0.8 = 0.72 W

· Sink-side output transistor power dissipation P4

P4 = V

(sink)

= 1.1 V

1 A = 1.10 W

· Total internal power dissipation P

P = P1 + P2 + P3 + P4 = 2.22 W

IC temperature Rise Measurement

Because the chip temperature of the IC cannot be measured directly, measurement according to one of the following
procedures should always be carried out.
· Thermocouple measurement

A thermocouple element is mounted to the IC heat dissipation fin. This measurement method is easy to implement, but
it will be subject to measurement errors if the temperature is not stable.

· Measurement using internal diode characteristics of IC

This is the recommended measurement method. It makes use of the parasitic diode incorporated in the IC between FG1
and GND. Set FG1 to High and measure the voltage V

of the parasitic diode to calculate the temperature.

(Sanyo data: for I

= 1 mA, V

temperature characteristics are about 2 mV/°C)

NC Pins

Because NC pins are electrically open, they may be used for wiring purpose etc.

No. 6087-11/12

LB1975

PS No. 6087-12/12

LB1975

This catalog provides information as of February, 2003. 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.

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