Diodes ZXBM2004 User Manual
Description
The ZXBM2004 is a 2-phase, Brushless Direct Current (BLDC)
motor control pre-driver with variable PWM speed control
suitable for fan and blower motors.
For system flexibility, motor speed can be controlled by
changing SPD pin voltage which can be either from Thermistor
network, external voltage or PWM signal.
To help protect the motor coil, the ZXBM2004 provides Rotor
Lock Protection which shuts down the output drive if rotor lock
is detected. The device automatically re-starts when the rotor
lock is removed.
NEW PRODUCT
A Tachometer output is provided by open-drain Frequency
Generator (FG) Pin which allows external interface to monitor
motor rotation or speed. The FG output is the magnetic
change frequency.
The ZXBM2004 is available in small space saving low prof ile
U-QFN3030-16 and QSOP-16 packages.
Features
• Supports two-phase BLDC motor control
• Operating voltage: 4.7V to 18V
o Can be extended with external regulator
• PWM speed control via external Thermister, DC voltage or
PWM signals
• Reference voltage output
• Built-in Hall amplifier allows direct connection of Hall
element
• Rotor Lock Protection (Lock detection, output shutdown
and automatic re-start)
• Rotor lock detect (RD) output
• Minimum speed setting
• Frequency generator (FG) output for speed measurements
• Low noise
• Space saving low profile U-QFN3030-16 and QSOP-16
packages
• “Green” Molding Compound
ZXBM2004
TWO PHASE VARIABLE SPEED
MOTOR CONTROL PRE-DRIVER
Pin Assignments
(Top View)
Ph1
Ph2
NC
FG
V
CC
V+OP
Ph1
Ph2
N/C
FG
RD
C
LCK
1
H+
H-
N/C
ThRef
SPD
C
PWM
S
MIN
GND
ZXBM2004
QSOP-16
(Top View )
CC
V+OP
V
H+
H-
NC
ThRef
SPD
C
PWM
MIN
S
GND
U-QFN3030-16
C
LCK
RD
Applications
• Desktop PC and Servers fans and blowers
• Instrumentation fans
• Central heating blowers
• Automotive instrument cooling and climate control
• Extractor fans
• General motors and pumps
ZXBM2004
Document number: DS33433 Rev. 5 - 2
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© Diodes Incorporated
Typical Application Circuit
NEW PRODUCT
ZXBM2004
TWO PHASE VARIABLE SPEED
MOTOR CONTROL PRE-DRIVER
Pin Descriptions
Pin Name Description
H+ Hall input to non-inverting input of internal operational amplifier
H- Hall input to inverting input of internal operational amplifier
ThRef Reference output voltage
SPD
C
PWM
S
MIN
GND Supply return ground pin
C
LCK
RD
FG Frequency Generator output to provide a tachometer signal
Ph1
Ph2
V+OP
VCC
ZXBM2004
Document number: DS33433 Rev. 5 - 2
Speed control pin; The control signal voltage should be bet ween 3V to 1V for 0% to 100 % (full speed)
speed control
PWM frequency setting pin: Connect a capacitor from this pin to ground (0V) to set PWM frequency.
Capacitor of 0.1nF will give PWM frequency of 24kHz typical.
Minimum speed setting pin: Voltage between 3V to 1V on this pin sets the minimum speed
between 0% to full speed. Lowest minimum speed achieved depends on the motor coil
design.
Rotor lock detect and auto re-start timing pin: Connect a capacitor from this pin to ground to set the lock
detect and restart timing.
Rotor lock detect pin: Open collector output to indicate rotor lock detection
Connect a pull-up resistor from the pin to the pull-up supply rail
Phase-1 low-side external power switch drive output pin: Darlington emitter follower output with active
pull down to give source/sink current of 80mA/16mA
Phase-2 low-side external power switch drive output pin: Darlington emitter follower output with active
pull down to give source/sink current of 80mA/16mA
Phase output supply voltage pin: The pin allows to optimiz e the supply to output drive depending on
whether external power switch is Bipolar switch or MOSFET
Power supply pin
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Functional Block Diagram (Note 1)
Supply Voltage
NEW PRODUCT
V
Speed Control Voltage
SPD
ThRef
C
PWM
SPD
SMIN
PWM Osc
Set Min
Speed
D1
Vref
ZXBM2004
TWO PHASE VARIABLE SPEED
MOTOR CONTROL PRE-DRIVER
D2
V
CC
Phase
Drive &
Control
V+OP
Set Phase Drive
Current Limit
Vcc
Ph1 Lo
Vcc
Ph2 Lo
L1
L2
Locked
Rotor
Detect
Hall
Amp
GND
Speed &
Lock
Detect
RD
FG
Vcc
Hall Bias
Hall
C
LCK
H+
H-
Notes: 1. The ZXBM2004 has an open-collector FG and RD. Typically a pull-up resistor of 10kΩ is recommended from FG or RD pin to the supply voltage.
ZXBM2004
Document number: DS33433 Rev. 5 - 2
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ZXBM2004
Absolute Maximum Ratings (T
Symbol Characteristics Values Unit
V
Note: 2. Stresses greater than the 'Absolute Maximum Ratings' specified above, may cause permanent damage to the device. These are stress ratings only;
functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. Device reliability
may be affected by exposure to absolute maximum rating conditions for extended periods of time.
NEW PRODUCT
3. U-QFN3030-16 dissipation is based on a two-layer 2oz. copper 2”x 2” FR4 substrate PCB with thermal vias to the bottom layer.
CCMAX
I
CCMAX
P
DMAX
TA
T
STG
Supply voltage -0.6 to +20 V
IC input current 100 mA
Power Dissipation (Note 4)
Operating ambient temperature -40 to +110
Storage Temperature Range -55 to +150
Recommended Operating Conditions (T
Symbol Parameter Conditions Min Max Unit
VCC
TA
Supply Voltage Operating
Operating Temperature Range Operating
Electrical Characteristics (T
Symbol Characteristics Conditions Min Typ. Max Unit
ICC
Supply Current No Load (Note 4) - 5.5 7.5 mA
VIN Hall amplifier input voltage Diff peak to peak 40 mV
VCM
V
VOH
V
V
IOH
I
PWMC
I
PWMD
V
V
F
Notes: 4. Measure with pins H+, H-, C
5. Measured when opposing Phase Output is Low
Hall amplifier common mode voltage 0.5
Hall amplifier input offset voltage ±7 mV
OFS
IBS
Hall amplifier bias current 400 700 nA
Ph1 and Ph2 output high voltage
Ph1 and Ph2 output low voltage
OLA
Ph1 and Ph2 output low voltage
OLB
Ph1 and Ph2 output source current 80 mA
IOL
Ph1 and Ph2 output sink current 16 mA
C
C
C
THH
C
THL
PWM
6. Measured when opposing Phase Output is High
charge current
PWM
discharge current
PWM
high threshold voltage
PWM
low threshold voltage
PWM
PWM frequency
LCK
and C
= 25°C, unless otherwise noted, Note 2)
A
QSOP-16 500
U-QFN3030-16 (Note 3) 1500
= 25°C)
A
= 25°C, V
A
CC
= 12V)
I
= 80mA V
OH
=16mA (Note 5)
I
OH
I
= 50uA (Note 6)
OH
4.5 7.85 µA
38 65 µA
3 V
1 V
C
= 0.1nF
PWM
and all other signal pins open circuit
PWM
TWO PHASE VARIABLE SPEED
MOTOR CONTROL PRE-DRIVER
4.7
-40
-2.2
CC
Vcc -1.8 V
0.4 0.6 V
0.4 0.6 V
24 kHz
18.0 V
+110
V
-1.5
CC
mW
oC
o
C
o
C
V
ZXBM2004
Document number: DS33433 Rev. 5 - 2
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Electrical Characteristics (cont.) (T
Symbol Characteristics Conditions Min Typ. Max Unit
V
ThRef reference output voltgae
ThRef
I
ThRef output current 1 mA
SPDL
SPDH
ISPD
S
C
C
input current V
MIN
SPD voltage minimum 100% PWM drive 1 V
SPD voltage maximum 0% PWM drive 3 V
SPD voltage maximum
charge current
LCK
discharge current
LCK
high threshold voltage
low threshold voltage
Lock condition On:Off ratio 1:12
FG Low level output current 5 mA
FG Low level output voltage
FGOL
RD Low level output current 5 mA
RD Low level output current
RDOL
tCD
Commutation delay 7.5 µs
NEW PRODUCT
OThRef
I
ISMIN
V
V
I
I
LCKC
I
LCKD
V
CLCKTHH CLCK
V
CLCKTHL CLCK
I
FGOL
V
I
RDOL
V
= 25°C, V
A
ZXBM2004
TWO PHASE VARIABLE SPEED
MOTOR CONTROL PRE-DRIVER
= 12V)
CC
I
= 100µA
OThRef
= 2V, SPD=open
IN
V
= 2V
IN
2.8 3.8 µA
4.6 054 µA
3 V
1 V
I
= 5mA
FGOL
I
= 5mA
RDOL
2.88 2.96 3.10 V
-0.25 -0.3 µA
0.8 2 µA
0.5 V
0.5 V
ZXBM2004
Document number: DS33433 Rev. 5 - 2
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ZXBM2004
Functional Descriptions
H+ and H- Hall Inputs
The rotor position is detected by a Hall sensor, with the output applied to the H+ and H-pins. This sensor can be either a 4 pin
'naked' Hall device or of the 3 pin buffered switching t ype. For a 4 pin dev ice the di fferential Ha ll output signal is co nnec ted to
the H+ and H-pins. For a buffered Hall sensor the Hall device output is attached to the H+ pin, with a pull-up attached if
needed, whilst the H-pin has an external potential divider attached to hold the pin at half V
H-, Ph2 is the active drive.
ThRef - Output Reference Voltage
This is a reference voltage of nominal 3V. It is designed for the abil ity to 'source' and therefore it will not 'sink' any current
from a higher voltage. The current drawn from the pin by the minim um speed potential divider to pin S
setting network should not exceed 1mA in total at maximum temperature.
NEW PRODUCT
SPD - Speed Control Input
The voltage applied to the SPD pin provides control over motor spee d by varying the Pulse Width Modulated (PWM) drive
ratio at the Ph1 and Ph2 outputs. The control signal takes the form of a voltage input of range 3V to 1V, representing 0% to
100% drive respectively.
If variable speed control is not required this pin can be left with an external potential divider to set a fixed sp eed or tied to
ground to provide full speed i.e. 100% PWM drive.
If required this pin can also be used as an enable pin. The application of a voltage >3.0V will force the PWM drive fully off, in
effect disabling the drive.
S
– Minimum Speed Setting
MIN
A voltage can be set on S
pin such that internally SPD voltage cannot rise above S
speed it therefore restricts the lower speed range of the fan. If this feature is not required the pin is left tied to ThRef so no
minimum speed will be set.
If the fan is being controlled from an external voltage source onto the SPD pin then either this feature should not be used or if
it is required then a resistor greater than 1kΩ should be placed in series with the SPD pin.
C
– Output PWM Frequency Setting
PWM
This pin has an external capacitor attached to set the PWM frequency for the Phase drive outputs. A cap acitor value of 0.1nF
will provide a PWM frequency of typically 24kHz. The C
()()
PWM
T
=
Where: C = (C
V
THH
I
PWMC
T
As these threshold voltages are nominally set to V
PWM
T +=
PWM
I
and V
C2
THLTHH
PWMC
I
PWM
and I
is in ms
PWMDPWMC
I
+15) in pF
THL
PWMD
C2
pin via a potential divider between the ThRef and Gnd. This voltage is monitored by the SPD
MIN
voltage. As a higher voltage on the SPD pin represents a lower
MIN
timing period (T
PWM
THLTHH
CVV
×−
+
are the C
are the charge and discharge currents in µA.
PWMD
I
PWM
CVV
×−
pin threshold voltages
= 3V and V
THH
= 1V the equations can be simplified as follows:
THL
TWO PHASE VARIABLE SPEED
MOTOR CONTROL PRE-DRIVER
. When H+ is high in relation to
CC
and any voltage
MIN
) is determined by the following equation:
PWM
ZXBM2004
Document number: DS33433 Rev. 5 - 2
6 of 19
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February 2012
© Diodes Incorporated
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