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DESCRIPTION

The ZXBM200x is a series of 2-phase, DC brushless motor pre-drivers with PWM

variable speed control suitable for fan and blower motors.

FEATURES

·

Built in lock detect protection, rotational speed sensing and automatic recovery

·

Built in Hall amplifier allows direct connection to Hall element

·

PWM Speed control can be implemented via external voltage or resistance (thermistor) input

·

Speed (FG) pulse output – ZXBM2003

·

Rotor lock output – ZXBM2002

·

Combined Rotor Lock (RD) and Speed (FG) signal – ZXBM2001

·

Up to 18V input voltage (60V with external regulator)

·

MSOP10 package

APPLICATIONS

·

Mainframe and Personal Computer Fans and Blowers

·

Instrumentation Fans

·

Central Heating Blowers

·

Automotive climate control

DEVICE MARKING

ZXBM2001 - BM21

ZXBM2002 - BM22

ZXBM2003 - BM23

ZXBM2001

ZXBM2002 ZXBM2003

ISSUE 1 - APRIL 2002

1

VARIABLE SPEED 2-PHASE FAN MOTOR CONTROLLER

DEVICE

REEL SIZE

TAPE WIDTH

QUANTITY PER REEL

ZXBM200xX10TA

7” (180mm)

12mm

1,000

ZXBM200xX10TC

13” (330mm)

12mm

4,000

ORDERING INFORMATION

Example: ZXBM2001X10TA

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ZXBM2001

ZXBM2002 ZXBM2003

ISSUE 1 - APRIL 2002

2

Parameter

Symbol

Limits

Unit

Supply Voltage

V

CCmax

-0.6 to 20

V

Input Current

I

CC

200

mA

Power Dissipation

P

D

500

mW

Operating Temp.

T

OPR

-40 to 85

ЊC

Storage Temp.

T

STG

-55 to 125

ЊC

Absolute maximum ratings

Parameter

Symbol

Min

Typ

Max

Unit

Conditions

Supply Voltage

V

CC

4.5

18

V

Supply Current

I

CC

2.2

3.25

mA

No Load

1

Hall Amp Input Voltage

40

mV

diff p-p

Hall Amp Common Mode Voltage

V

CM

0.5

0.5V

CC

V

CC

-1.5

V

Hall Amp Input Offset

V

OFS

±7

mV

Hall Amp Bias Current

V

BS

-350

nA

PH1, PH2 Output High

V

OH

V

CC

-2.2

V

CC

-1.8

V

I

OH

= 80mA

PH1, PH2 Output Off Leakage

Current

I

OFF

Ϯ10

␮A

PH1, PH2 Output Current

I

OL

80

mA

Lock/FG Maximum Collector

Voltage

V

OH

V

CC

V

Lock/FG Sink Current

I

OL

5

mA

Lock/FG Low Level O/P Voltage

V

OL

0.3

0.5

V

I

OL

= 5mA

C

LCK

Charge Current

I

LCKC

-1.8

-2.8

␮A

V

in

= 1.5V

C

LCK

Discharge Current

I

LCKD

0.28

0.35

␮A

V

in

= 1.5V

Lock condition On:Off ratio

1:7

1:10

C

LCK

High Threshold Voltage

V

THH

2.0

V

C

LCK

Low Threshold Voltage

V

THL

1.0

V

C

PWM

Charge Current

I

PWMC

3.6

4.3

5.0

␮A

V

in

= 1.5V

C

PWM

Discharge Current

I

PWMD

50

62

75

␮A

V

in

= 1.5V

PWM Frequency

F

PWM

24

kHz

C

PWM

=

0.15nF

C

PWM

High Threshold Voltage

V

THH

2.0

V

C

PWM

Low Threshold Voltage

V

THL

1.0

V

SPD Voltage Control Range

V

SPD

1

2

V

2

SPD Open Circuit Voltage

1.5

V

3

Electrical Characteristics (at Tamb = 25°C & Vcc = 12V)

Notes:

1

Measured with pins H+, H-, CLCK and CPWM = 0V and all other signal pins open circuit.

2

The 1V minimum represents 100% PWM drive and 2V represents 0% PWM drive.

3

This voltage is determined by an internal resistor network of 52.5k

⍀ from the pin to Gnd and 19.5k⍀ from the pin to a 2V reference. Whilst both

resistors track each other the absolute values are subject to a

Ϯ20% manufacturing tolerance.

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Block Diagram (ZXBM2001):

Pin Assignments

ZXBM2001

ZXBM2002 ZXBM2003

ISSUE 1 - APRIL 2002

3

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Pin Functional Descriptions

1. VCC

- Applied voltage

This is the device supply voltage. For 5V to 12V fans this

can be supplied directly from the Fan Motor supply. For

fans likely to run in excess of the 18V maximum rating

for the device this will be supplied from an external

regulator such as a zener diode.

2. H+

- Hall input

3. H-

- Hall input

The rotor position of the Fan Motor is detected by a Hall

sensor whose output is applied to these pins. This

sensor can be either a 4 pin ‘naked’ Hall device or a 3

pin buffered switching type. For a 4 pin device the

differential Hall output signal is connected to the H+

and H- pins. For a 3 pin buffered Hall sensor the Hall

device output is attached to the H+ pin whilst the H- pin

has an external potential divider attached to hold the

pin at half V

CC

. When H+ is high in relation to H- Ph2 is

the active drive.

4. SPD

-  Speed control voltage input

This pin provides control over the Fan Motor speed by

varying the Pulse Width Modulated (PWM) drive ratio

at the Ph1 and Ph2 outputs. This control signal can take

the form of either a voltage input of nominal range 2V

to 1V, representing 0% to 100% drive respectively, or

alternatively a thermistor can be attached to this pin to

control the voltage. The pin has an internal potential

divider between Gnd and an internal 2.0V reference

designed to hold the pin at approximately 1.5V. This

will represent a drive of nominally 50%. The addition of

a 100k NTC thermistor to ground, for example, will

provide a drive nominally 70% at 25°C and 100% at

50°C.

If speed control is not required this pin is can be left

open circuit for 50% drive or tied to ground by a 10k

resistor to provide 100% drive.

If required this pin can also be used as an enable pin.

The application of a voltage of 2.0V to V

CC

will to force

the PWM drive fully off, in effect disabling the drive.

5. GND

-  Ground

This is the device supply ground return pin and will

generally be the most negative supply pin to the fan.

6. LOCK/FG

- Locked Rotor error output /

Frequency Generator (speed) output

On the ZXBM2001 the Lock/FG pin is designed to be a

dual function pin to provide an indication of the Fans

rotational speed together with an indication of when

the Fan has failed rotating for whatever reason (Rotor

Locked condition). The pin is an open collector drive,

that is there is an active pull down with the high level

being provided by an external pull up resistor. Under

correct operating conditions, and with this external

pull-up in place, this pin will provide an output signal

whose frequency will be twice that of the rotational

frequency of the fan. Should the fan itself stop rotating

for any reason, i.e. an obstruction in the fan blade or a

seized bearing, then the device will enter a Rotor

Locked condition. In this condition the Lock/FG pin will

go high (regardless of the state of the Hall sensor)

when the C

LCK

pin reaches the V

THH

threshold and will

remain high until the fan blades start rotating again.

On the ZXBM2002 variant this pin is Lock. During

normal operation the signal will be low and during a

Locked Rotor condition the pin will go high when the

C

LCK

pin reaches the V

THH

threshold.

For the ZXBM2003 variant this pin is FG. This signal is a

buffered and inverted output of the Hall signal and

therefore provides an output signal whose frequency

will be twice that of the rotational frequency of the fan.

7. C

LCK

- Locked Rotor timing capacitor

When in a Locked Rotor condition as described above

the Ph1 and Ph2 drive outputs go into a safe drive mode

to protect the external drive devices and the motor

windings. This condition consists of driving the motor

for a short period then waiting for a longer period

before trying again. The frequency at which this takes

place is determined by the size of the capacitor applied

to this CLCK pin. For a 12V supply a value of 1.0uF will

typically provide an ‘On’ (drive) period of 0.33s and an

‘Off’ (wait) period of 4.0s, giving an On:Off ratio of 1:12.

ZXBM2001

ZXBM2002 ZXBM2003

ISSUE 1 - APRIL 2002

4

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Locked Rotor timing capacitor (CONT).

The C

LCK

timing periods are determined by the

following equations:

T

V

C

I

THH

LCK

LCKC

lock

=

×

T

V

V

C

I

THH

THL

LCK

LCKD

off

=

×

(

)

T

V

V

C

I

THH

THL

LCK

LCKC

on

=

×

(

)

Where V

THH

and V

THL

are the C

LCK

pin threshold

voltages and I

LCKC

and I

LCKD

are the charge and

discharge currents.

As these threshold voltages are nominally set to

V

THH

=2V and V

THL

=1V the equations can be simplified

as follows:

T

C

I

LCK

LCKC

lock

=

×

2

T =

C

I

on

LCK

LCKC

T

C

I

LCK

LCKD

off

=

8. C

PWM

- Sets PWM frequency

This pin has an external capacitor attached to set the

PWM frequency for the Phase drive outputs. A

capacitor value of 0.15nF will provide a PWM

frequency of typically 24kHz.

The C

LCK

timing period (T

pwm

) is determined by the

following equation:

T

V

V

C

I

V

V

C

I

THH

THL

PWM

PWMC

THH

THL

PWM

PWMD

pwm

=

×

+

×

(

)

(

)

Where V

THH

and V

THL

are the C

PWM

pin threshold

voltages and I

PWMC

and I

PWMD

are the charge and

discharge currents.

As these threshold voltages are nominally set to

V

THH

=2V and V

THL

=1V the equations can be simplified

as follows:

T

C

I

C

I

PWM

PWMC

PWM

PWMD

pwm

=

+

9. PH2

- External transistor driver

10. PH1

- External transistor driver

These are the Phase drive outputs and are open

darlington emitter followers designed to provide up to

80mA of drive to external transistors as shown in the

Application circuits following. The external transistors

in turn drive the fan motor windings.

Lock Timing Example:

Using the equation previously described and to be

found under the C

LCK

pin description:

T

C

I

LCK

LCKC

lock

=

×

2

T

C

I

LCK

LCKC

on

=

T

C

I

LCK

LCKD

off

=

Using a value of C

LCK

= 1.0uF together with the values

of I

LCKC

and I

LCKD

to be found in the Electrical

Characteristics we can derive the following timings for

operation at 12V and 25°C.

T

=

2 1.0 F

2.8 A

lock

×

=

0 714

.

s

T

=

1.0 F

0.28 A

off

=

3 6

.

s

T =

2 1.0 F

2.8 A

on

×

=

0 36

.

s

ZXBM2001

ZXBM2002 ZXBM2003

ISSUE 1 - APRIL 2002

5

Lock and FG Timing Waveform:

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APPLICATION INFORMATION

The ZXBM200x series of 2-phase DC brushless motor

pre-drivers are capable of driving both Bipolar or

MOSFET power transistors.

For smaller fans and blowers it is likely that bipolar

power transistors would be used as shown in the

following Applications circuit.

In Figure 1, R1 & R2 have their value selected to provide

suitable base current in keeping with the winding

current and gain of the power transistors Q1 & Q2. R3 &

R4 have their value selected to provide efficient

switch-off of Q1 & Q2. The Zener diodes ZD1 & ZD2

provide active clamping in conjunction with Q1 & Q2.

It is also recommended that the supply de-coupling

capacitor C3 is positioned as close as is practical to the

ZXBM device pins.

In the case of higher power fans and blowers it may be

more applicable to use MOSFET devices to switch the

windings as illustrated in the second applications

circuit shown in Figure 2.

In Figure 2, the Resistor ratio of R1 to R3 and R2 to R4

provide the required Gate turn-on voltage whilst the

absolute values will be chosen to provide sufficient

gate switching currents.

Also illustrated in the two Applications circuits above

are the methods of connection for both a ‘naked’ Hall

device, as seen in the bipolar circuit in Figure 1, and a

buffered Hall device, as in the MOSFET circuit in Figure

2. In this latter circuit R5 & R6 bias the H- pin at a voltage

equivalent to half the swing of the Hall device. R7 will

be needed if the buffered Hall device does not have its

own internal pull-up.

Graph 1 below, illustrates the PWM drive waveform

taken from and application using the MOSFET circuit in

Figure 2. This shows the waveforms to be found at the

Ph1 output and at the drain/Winding node.

ZXBM2001

ZXBM2002 ZXBM2003

ISSUE 1 - APRIL 2002

6

TYPICAL APPLICATION (ZXBM2001) using

Bipolar power transistors

Figure 1

TYPICAL APPLICATION (ZXBM2001) using

MOSFET power transistors

Figure 2

Graph 1

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When driving fans with bipolar transistors, at higher

voltages it may be necessary to provide extra noise

protection by the addition of a diode from the driver

collector to Gnd on each phase. This prevents negative

voltage excursions from the windings affecting

operation. See Figure 3 right, showing the placement

of these diodes. It should be noted that these are not

required for the MOSFET solution in Figure 2 as the

diodes are inherent in the MOSFET structure.

Zetex provide a variety of suitable power transistors for

using with the ZXBM200x series of 2-phase DC

brushless motor pre-drivers and suitable devices

sufficient for a range of applications are given in the

following table.

ZXBM2001

ZXBM2002 ZXBM2003

ISSUE 1 - APRIL 2002

7

Bipolar Types

V

CEO

(V)

I

C

(A)

min H

FE

@ I

C

V

CE(sat)

max

(mV)

@ I

C

& I

B

Package

FZT1053A

75

4.5

300 @ 0.5A

200@1A,10mA

SOT223

FZT851

60

6

100 @ 2A

100@1A,10mA

SOT223

ZXT13N50DE6

50

4

300 @ 1A

100@1A,10mA

SOT23-6

MOSFET Types

BV

DSS

(V)

I

D

(A)

I

PEAK

(A)

(Pulsed)

R

DS(on)

(mW)

@ V

GS

Package

ZXMN3A04DN8

2 3

30

7.6

25

20 @ 10V

SO8

ZXMN6A09DN8

2 3

60

5

17.6

45 @ 10V

SO8

SUMMARY TABLE OF SUITABLE DEVICES

Notes:

1

Contact your nearest Zetex office for further details and technical enquiries.

2

Dual device

3

Provisional  information

4

Advanced  information

Figure 3

TYPICAL APPLICATION (ZXBM2001)

illustrating addition of Clamp diodes.

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Zetex plc

Fields New Road

Chadderton

Oldham, OL9 8NP

United Kingdom

Telephone (44) 161 622 4422

Fax: (44) 161 622 4420

Zetex GmbH

Streitfeldstraße 19

D-81673 München

Germany

Telefon: (49) 89 45 49 49 0

Fax: (49) 89 45 49 49 49

Zetex Inc

700 Veterans Memorial Hwy

Hauppauge, NY11788

USA

Telephone: (631) 360 2222

Fax: (631) 360 8222

Zetex (Asia) Ltd

3701-04 Metroplaza, Tower 1

Hing Fong Road

Kwai Fong

Hong Kong

Telephone: (852) 26100 611

Fax: (852) 24250 494

These offices are supported by agents and distributors in major countries world-wide.

This publication is issued to provide outline information only which (unless agreed by the Company in writing) may not be used, applied or reproduced

for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services concerned. The Company

reserves the right to alter without notice the specification, design, price or conditions of supply of any product or service.

For the latest product information, log on to

www.zetex.com

© Zetex plc 2002

ZXBM2001

ZXBM2002 ZXBM2003

ISSUE 1 - APRIL 2002

DIM

MILLIMETRE

MIN.

MAX.

A

1.10

A1

0.15

A2

0.75

0.95

D

3.00 BSC

E

4.90 BSC

E1

3.00 BSC

b

0.17

0.27

c

0.08

0.23

e

0.50 BSC

0

Њ

15

Њ

L

0.40

0.80

L1

0.95 BSC

PACKAGE DIMENSIONS

Conforms to JEDEC MO-187 VARIATION BA

8