WELTREND WT7062

偉詮電子股份有限公司
Weltrend Semiconductor, Inc.
WT7062
3-Phase Sensorless Motor Driver
Data Sheet
REV. 0.05
March 4, 2011
Weltrend Semiconductor, Inc.
Proprietary & Confidential
Mar. 4, 2011
Rev. 0.05
Page i
WT7062
3-Phase Brushless Sensorless DC Motor Driver
Revision History
Version
0.01
0.02
Content
First released
Date
August 3, 2010
1. Added pin description and DFN-10 outline drawing
2. Modified Supply current
August 24, 2010
1. Added DFN10 Theta Ja, Jc, Tjmax, Pdmax
0.03
2. Modified MSOP10 Theta Ja, Jc, Tjmax, Pdmax
3. Modified PWM VPWML, VPWMH
September 16, 2010
4. Modified LDT, LRT
0.04
0.05
1. Described FR function and Added LHT, LRT
2. Modified LDT, LRT
1. Added FIL Pin and modify Application circuit
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March 4, 2011
Mar. 4, 2010
Rev. 0.05
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WT7062
3-Phase Brushless Sensorless DC Motor Driver
Generation Description
The WT7062 is 3-phase full-wave drivers for brushless sensorless DC motors. It features 150°
square drive, high torque output, and silent drive. Speed control can be achieved through either
power supply modulation or pulse-width-modulation (using the PWM digital input pin).
Due to the compact packaging and minimum bill-of-material (power transistors incorporated, no
Hall sensor, no external tuning), they are best suited for low-cost fan applications requiring high
efficiency and low acoustic noise, such as notebook cooling fans.
Frequency generator output is also included (FG). The WT7062 driver includes a lockup protection
mode, which turns-off the output current when the motor is under lock condition, and an automatic
recovery that enables the fan to release when the lock condition is removed. Thermal-shutdown
protection is also included. They are available in a compact thermally-enhanced MSOP10
package.
Features
 Position sensorless BLDC drivers (no Hall sensor required)
 150° square drive, for high efficiency and low acoustic noise
 Support 2.0V to 5.5V power supplies
 Speed control through PAM or PWM
 Built-in frequency generator (FG output signal)
 Built-in lockup protection and automatic recovery circuit (external capacitors not necessary)
 Built-in thermal shutdown protection
 MSOP-10 & DFN-10 package
 No external tuning required
Weltrend reserves the right to change this documentation without prior notice. Information provided by Weltrend is believed to be accurate and
reliable. However, Weltrend makes no warranty for any errors which may appear in this document. Contact Weltrend to obtain the latest version of
device specifications before placing your order. No responsibility is assumed by Weltrend for any infringement of patent or other rights of third parties
which may result from its use. In addition, Weltrend products are not authorized for use as critical components in life support devices/ systems or
aviation devices/systems, where a malfunction or failure of the product may reasonably be expected to result in significant injury to the user, without
the express written approval of Weltrend
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Block Diagram
PWM
FG
UV W
10
MUX
1
FIL
COM
9
2
VREF
CMP
OSC
Controller
Logic
FR
3
TSD
VSS
8
Pre-Driver
VCC
V
4
7
U
W
5
6
Figure 1: block diagram
Pin Assignments
FG
1
10 PWM
FG
1
10 PWM
COM
2
9
FIL
COM
2
9
FIL
FR
3
8
VSS
FR
3
8
VSS
VCC
4
7
V
VCC
4
7
V
U
5
6
W
U
5
6
W
Figure 2: DFN-10 & MSOP-10 pin assignments
Pin Description
Pin No.
Pin name
Function
Equivalent circuit
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1
FG
2
VCOM
3
FR
VCC
FG pulse output.
VCC
Motor middle point connection.
VCC
Motor rotation direction
switching. A low level input
(0~0.3Vcc) causes forward
500Ω
rotation. A middle level input
(0.3Vcc~0.7cc) makes the
20kΩ
motor locked. And a high level
input (0.7Vcc~Vcc) causes
reverse rotation.
4
VCC
5
U
Power supply
VCC
Output pin.
Connect the motor coil.
6
W
V
U
7
V
8
GND
9
FIL
Ground for IC
Motor position detection filter
VCC
pin. Connect a capacitor
between this pin and the
VCOM pin.
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W
10
PWM
VCC
PWM signal input. The motor
speed is controlled by the input
8kΩ
PWM duty cycle setting.
500Ω
Pin Functions
Pin #
1
2
3
4
5
6
7
8
9
10
Pin Name
FG
COM
FR
VCC
U
W
V
VSS
FIL
PWM
Pin Description
Motor speed indication output (open drain)
Motor middle point terminal
Motor rotation direction switching
Power Supply for the IC and motor
U phase output terminal
W phase output terminal
V phase output terminal
Ground terminal
Motor position detection filter pin
PWM input signal for speed control
Figure 4: MSOP-10/DFN-10 pin assignments
Functional Description
The WT7062 generates signals to drive a 3-phase sensorless BLDC motor. High efficiency and
low-power consumption are achieved due to synchronous rectification drive type. The current carrying
order of the outputs is as follows: U phase -> V phase -> W phase.
Speed Control
The rotational speed of the motor can be controlled either through the PWM digital input
signal or by acting directly on the power supply (VCC). When the PWM signal is “High” (or
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left open) the motor rotates at full speed. When the PWM signal is “Low” the motor is
stopped (and the IC outputs are set to high-impedance). By changing the PWM duty cycle,
the speed can be adjusted. Notice that the PWM frequency has no special meaning for the
motor speed and is asynchronous with the activation of the output transistors. Thus the user
has maximum freedom to choose the PWM system frequency within a wide range (from
20KHz to 50kHz)
Frequency Generator Function
The Frequency Generator output (FG) is a “Hall-sensor equivalent” digital output, giving
information to an external controller about the speed and phase of the motor. When a lock
(or out-of-sync) situation is detected by the driver, this output is set to “Low” until the motor is
restarted. The FG pin is an open collector output, connecting to a logical voltage level
through an external pull-up resistor. Leave the pin open when not used.
Lockup Protection and Automatic Restart
If the motor is stopped (blocked) or if it loses synchronization with the driver, a lock-up
protection circuit detects this situation and disables the driver (by setting its outputs to
high-impedance) in order to prevent the motor coil from burnout. After a "release time" (LRT),
the lock-up protection is released and normal operation resumes for a given time (LDT). In
case of the motor is still blocked, a new period of waiting time is started. LRT and LDT
timings are fixed internally, so that no external capacitor is needed.
Figure 4 Lock and FG timing charts
Thermal Shutdown
The WT7062 has a thermal protection function which detects when the die temperature
exceeds Tj=150°C. When this temperature is reached, the circuit enters the thermal
shutdown mode and the outputs U phase, V phase and W phase are disabled (high
impedance), avoiding IC destruction and allowing the circuit to cool down. Once the junction
temperature (TJ) has dropped below 120°C, the normal operation resumes (thermal
detection circuit has 30°C hysteresis function).
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Figure 5 Thermal protection hysteresis
Positional Detection Filter
The positional detection problems caused by a comparator input noise is improvable by
connecting a capacitor (0.1uF) between the VCOM and the FIL pin.
U,V,W phase and FG output signals
The timing charts of the output signals from the U, V and W phases as well as the FG
terminal are shown as below. Assuming that a three-slot tetrode motor is used, two pulse
outputs of FG are produced for one motor cycle. The three phases are excited in the order of
U, V and W phases.
U phase
voltage
V phase
voltage
W phase
voltage
FG
Figure 6: U, V, W and FG timing charts
FR function
FR pin is the motor rotational direction switching pin.
Low level voltage input : U → V → W,
High level voltage input : U → W → V
Perform a current – carrying to the motor in above order. The motor is revolving in the other
direction by exchanging the current – carrying order.
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Forward
Induced electromotive
voltage detection
Stop
Float
FHT
FRT
Backward
FR
FG
Figure 7: FR and FG timing charts
FR
3
FR1
0.7Vcc
5KO
FR2
0.3Vcc
0.7VCC
0.3VCC
FR
FR1
FR2
Forward
Stop
(V-PMOS, W-NMOS Turn-on)
LHT
Floating
Reverse
FRT
Stop
(V-PMOS, U-NMOS Turn-on)
LHT
Floating
Reverse
FRT
When the motor is running Forward (FR<0.3Vcc) or Reverse (FR>0.7Vcc) , if FR goes
to the voltage between 0.3Vcc to 0.7Vcc, WT7062 will deliver a stop signal to hold the motor.
When the motor is hold (0.3Vcc < FR < 0.7Vcc), if FR goes to the voltage less than 0.3Vcc or
larger than 0.7Vcc, WT7062 will let the motor float for 1 Sec and then back to the forward or
reverse mode.
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ELECTRICAL SPECIFICATIONS
Absolute maximum ratings at Ta= 25℃
℃
Parameter
Power Supply Voltage
Output pin current
PWM input pin voltage
FG output pin voltage
FG output pin current
Allowable Power Dissipation 1
Allowable Power Dissipation 2
Operating Temperature
Storage Temperature
Symbol
Vcc max
Iout max
VPWM max
VFG max
IFG max
Pd max 1
Pd max 2
Topr
Tstg
Ratings
6.5
600*
6.5
6.5
5
600
683
-30 ~ +95
-40 ~ +150
Unit
V
mA
V
V
mA
mW
mW
℃
℃
Conditions
MSOP10
DFN10
* This value is not to exceed Pd
Recommended operating conditions
Parameter
Symbol
Limit
Unit
Operating supply voltage range
VCC
2 ~ 5.5
V
Electrical Characteristic(Vcc=5V,Ta=25℃unless otherwise noted)
Parameter
Supply current (standby current)
Source + Sink
Output voltage
PWM pin high-level input voltage
PWM pin low-level input voltage
PWM input frequency
FG low voltage
Lock protection detection time
Lock protection release time
Thermal protection temperature
Thermal protection hysteresis
FR pin high-level input voltage
FR pin low-level input voltage
FR hold time
FR release time
Symbol
Icc
Ron(H+L)
VO
VPWMH
VPWML
Fpwm
VFGL
LDT
LRT
TSD
∆TSD
VFRH
VFRL
FHT
FRT
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Min
1
1.2
0.5
2.5
0
20
0.2
0.64
3.2
3.5
0
0.64
0.64
Ratings
Typ
-
1
5
150
30
1
1
Unit
Max
1.5
1.5
0.75
Vcc
0.6
50
0.4
1.42
7.11
5
1.5
1.42
mA
V
V
V
kHz
V
s
s
℃
℃
V
V
s
s
Conditions
PWM=GND
Iout =0.5A,
Iout =0.5A,
IFG=5mA
VDD=5V
Reverse
Forward
Stop
Float
Mar. 4, 2011
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Application Notes
PWM
FG
10
FIL
COM
9
2
VREF
CMP
C3
C4
330pF
FR
3
FR
PWM
MUX
1
FG
UV W
Controller
Logic
OSC
TSD
330pF
C2
0.1uF
VSS
8
Pre-Driver
VCC
V
4
VCC
C1
7
1uF
U
W
5
6
Package Outlines
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Package: 10-Lead MSOP (3x5x1.1mm)
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Package: 10-pin DFN (3x3x0.5mm)
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Carrier Tape & Reel Dimensions
Package: 10-Lead MSOP
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Package: 10-pin DFN
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Ordering Information
Part Number
Package Type
10-Pin MSOP, Green Package
10-Pin DFN, Green Package
WT7062-MG100
WT7062-VG100
Transport Media
Tape & Reel
Tape & Reel
Quantity
2,500
2,500
Allowable Power Dissipation , Pd max - mW
Thermal De-rating Curve
MSOP10
700
600
500
400
300
200
100
0
25
50
75
95
125
150
Ambient Temperature, Ta –°C
Allowable Power Dissipation , Pd max - mW
*70mm × 70mm × 1.6mm single layer board.
*ΘJa=208 ℃/W, ΘJc= 48 ℃/W, Tj max= 150℃, Pd max 600mW.
DFN10
683
600
500
400
300
200
100
0
25
50
75
95
125
150
Ambient Temperature, Ta –°C
*70mm x 70mm x 1.6mm single layer board.
*ΘJa=182.9 ℃/W, ΘJc= 33.6 ℃/W, Tj max= 150℃, Pd max 683mW.
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