Sony CXA3537TN Fan motor driver adopting the power-saving ddc drive system Datasheet

Fan Motor Driver Adopting the Power-saving DDC Drive System
CXA3537EN
CXA3537TN
■
Single-phase full-wave drive type fan
motor drivers
■
Maximum output current: 300 mA
■
Power-saving drive provided by the
DDC (drive duty control) system
To contribute to solving this problem, we proposed a new motor
■
drive system, the DDC system*1, to reduce fan motor power consumption, and developed the CXA3537EN/TN, which adopts this
The speed of motor rotation can be
changed by tap switching
■
Low output saturation voltage for low
loss
■
Wide operating voltage range:
3.0 to 13.2 V
■
FG outputs, thermal protection circuit
■
Ultrasmall package (CXA3537EN)
While rapid progress continues in portable information equipment
such as notebook personal computers, the associated increases
in power consumption mean that handling the heat generated has
become a critical problem.
system.
We showed experimentally that this drive system improves power
consumption by approximately 30% over conventional drive
systems.
At the same time, we also proposed a procedure for rapidly responding to the resonant vibration problem by adding a motor
speed modification function.
The CXA3537EN and CXA3537TN are
single-phase full-wave drive type fan
motor drivers.
The CXA3537EN is provided in an
ultrasmall 12-pin VSON package, and
the CXA3537TN is provided in a 16pin TSSOP package. The CXA3537TN
features isolation of the drive block
power supply pins from the IC power
supply pins, and provides stable motor
rotational speed control.
V
O
I
C
E
We found that when we adopted
the DDC system for use with power
consumption 1.2 W small fan
motors, power consumption was
reduced to 0.8 W. Although the
average drive torque provided by
the DDC system is lower than that
provided by conventional drive
system, in our tests, the speed of
motor rotation only fell by 6%. That
means that the difference of 0.4 W
has simply been lost as heat in
earlier circuits. This is truly wasteful. I strongly recommend that fan
motor manufacturers adopt the
CXA3537.
DDC System
for Power-saving Drive
While conventional single-phase fullwave drive systems apply drive current
regardless of the rotation angle position
of the rotor, there are ranges of rotor
rotation angle positions where the drive
torque generation efficiency with respect to the drive current is good, and
there are ranges of rotor rotation angle
positions where that efficiency is poor.
(See figure 1.) The DDC system does
not apply drive current at rotation angles
where the drive torque generation efficiency is low, but rather applies drive
mainly at rotation angles where the
efficiency is high. This allows power
consumption to be reduced. (See figure
2.) However, since the average drive
torque with the DDC system is lower
than that provided by conventional
single-phase full-wave drive systems,
problems, such as longer fan motor
startup times, do appear at low-speed
area. The CXA3537EN and CXA3537TN
use a conventional drive system that
provides higher torque at startup and at
low-speed area, and automatically
switch to the power-saving DDC system in the vicinity of the fan motor rated
speed.
*1 Patent applied for.
The Speed of Motor
Rotation can be Changed
The DDC system allows the speed of
motor rotation to be changed by changing the drive duty. The CXA3537EN/
TN provide two taps to switch the drive
duty, and thus one of four speeds can
be selected by switching the taps. (See
figures 3 and 4.)
Low Output Saturation
Voltage for Low Loss
The CXA3537EN and CXA3537TN
adopt newly-developed low saturation
voltage transistors in the output stage.
At the same time as compensating for
the loss in average drive torque due to
the DDC system, this also reduces circuit loss.
Ultrasmall package
The CXA3537EN is provided in a
VSON (Very Thin Small Outline
Non-leaded package) package. It features a mounting size of 2.7 × 3.5 mm
and a maximum mounting height of 0.9
mm. Thus this device supports the small
circuit boards used with small fan
motors. (See figure 5.)
(a) Hole signal
(a) Hole signal
■ Figure 2 Operating Waveforms of a DDC System Drive
■ Figure 1 Operating Waveforms of a Conventional
Single-phase Full-wave Drive
Conventional single-phase
full-wave drive
1.2
DDC system
This system achieves a 34%
reduction in power consumption with
only a 6% drop in motor speed.
1.0
0.8
0.6
0.4
6000
5500
5000
4000
3500
3000
2500
0.0
4500
CXA3537: This device allows one
of four motor speeds to be selected
by switching the taps.
0.2
2000
Fan motor power consumption [W]
360
Rotor rotation angle
(electrical angle) [deg]
Rotor rotation angle
(electrical angle) [deg]
1.4
270
180
0
360
270
(c) Drive torque
180
(c) Drive torque
90
(b) Drive current
0
(b) Drive current
90
The drive current is only applied
when good efficiency can be obtained.
The drive current is
always applied.
Speed of fan motor rotation [rpm]
■ Figure 3 Power-saving Effects of a DDC
System Drive and Variable-speed
Function (Experimentally verified
results)
VCC
C3
Hall
R2
10
9
8
VCC
OUT2
HIN1
HIN2
11
7
7
6
OUT1
5
GND
4
SEL2
3
SEL1
2
FG
REXT
1
12
LOAD
CXA3537EN
+0.1
0.8 –0.05
3.5
2.7
12
CHLD
C2
CEXT
C1
FG
R1
Open/short
Jumper selector
■ Figure 4 CXA3537EN Application Circuit
GND
1
6
0.5
■ Figure 5 CXA3537EN Package Dimensions (Provisional)
Similar pages