ACE705146BN+ [ACE]
High efficiency, Low supply current, step-up DC/DC Controller; 高效率，低电源电流，升压型DC / DC控制器
| 型号： | ACE705146BN+ |
| 厂家： | 
ACE TECHNOLOGY CO., LTD. |
| 描述： | High efficiency, Low supply current, step-up DC/DC Controller |
| 文件： | 总14页 (文件大小：651K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
ACE705
High efficiency, Low supply current, step-up
DC/DC Controller
Technology
Description
The ACE705 series are CMOS-based PFM step-up DC-DC Controller with low supply current and high
output voltage accuracy. Quiescent current drawn from power source is as low as 6uA. It is capable of
delivering 500mA output current at 4.0V output with 2V input Voltage. Only four external components are
necessary: An inductor, a Schottky diode, an output filter capacitor and a NMOSFET or a NPN transistor
All of these features make ACE705 series be suitable for the portable devices, which are supplied by a
single battery to four-cell batteries.
ACE705 has a drive pin (EXT) for external transistor. So it is possible to load a large output current with
a power transistor which has a low saturation voltage.
ACE705 integrates stable reference circuits and trimming technology, so it can afford high precision and
low temperature-drift coefficient of the output voltage.
ACE705 is available in SOT-23-3 and SOT-23-5 packages which are PB free. And in SOT-23-5 the
device can be switch on or off easily by CE pin, to minimize the standby supply current.
Features
• Deliver 500mA at 4.0V Output voltage with 2.0V input Voltage
• The converter output voltage can be adjusted from 2.5V～6.0V(In 0.1V step)
• Output voltage accuracy -----------±2％
• Low temperature-drift coefficient of the output voltage------------------±100ppm/℃
• Only four external components are necessary: An inductor, a Schottky diode an output filter
capacitor and a NMOSFET or a NPN transistor
• High power conversion efficiency---90％
• Low quiescent current drawn from power source------------------------------------- 6uA
Application
• Power source for PDA. DSC. MP3 Player. electronic toy and wireless mouse
• Power source for a single or dual-cell battery-powered equipments
• Power source for LED
Absolute Maximum Ratings
Parameter
Input voltage range
Input voltage
Symbol
Max
Unit
-0.3~12
V
V(EXT) -0.3~Vout+0.3 V
-0.3~Vout+0.3 V
CE pin voltage
EXT pin output current
0.7
A
Maximum power dissipation, Pd T=25℃
SOT-23-5
SOT-23-3
0.25
0.15
W
Maximum junction temperature
Operating free-air temperature range
Storage temperature range
150
℃
℃
℃
-20~80
-40~125
VER 1.2
1
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
Packaging Type
SOT-23-3
SOT-23-5
3
5
4
1
2
1
2
3
Pin
VSS(GND)
VOUT
SOT-23-3 SOT-23-5
Function
Ground pin
Output pin, power supply for internal circuits
Switching pin
1
2
3
4
2
5
3
1
Ext
NC
CE
Chip enable pin (active high)
Ordering information
Selection Guide
ACE705 X XX XX + H
Halogen - free
Pb - free
BN : SOT-23-5
BM : SOT-23-3
Output Voltage :
2.5V / 3.0V ….. 6.0V
Function Description :
1 : Without Enable circuit
2 : With Enable circuit
VER 1.2
2
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
Block Diagram
ACE705
Recommended Work Conditions
Item
Min Nom Max Unit
0.8 Vout V
10 27 100 μH
0 ≧10 μF
47 100 220 μF
Input voltage range
Inductor
Input capacitor
Output capacitor
Vout pin filter capacitor
Operating junction temperature -20
1
nF
85 OC
*Suggestion: Use tantalum type capacitor to reduce the ripple of the output voltage. Use 1nF filter ceramic type
capacitor to connect Vout pin and GND pin. The filter capacitor is recommended as close as possible to Vout pin
and GND pin.
Electrical Characteristics
Default condition (unless otherwise provided): Vin=0.6xVout, Iout=10mA.Temperature=25℃. Use external
circuit in test circuit list.
Parameter
Output Voltage
Input Voltage
Symbol
Test Conditions
Min Typ Max Unit
2.45 2.5 2.55
2.646 2.7 2.754
2.94 3.0 3.06
3.234 3.3 3.366
V
Vout
3.528 3.6 3.672
3.92 4.0 4.08
4.9
5.0
5.1
5.88 6.0 6.12
12
Vin
V
VER 1.2
3
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
Input Current * (no
load)
Lin
Iout=0mA, Vin=Vout*0.6
20
6
25
uA
No external component,
Vout=Voutx1.05
VCE=0V
Quiescent current *
IDD
8
1
uA
uA
V
Chip leakage current
CE “H: threshold
voltage
Istandby
VCEH
VCE:0Æ2V
VCE:2Æ0V
0.6
0.9
0.3
CE “L” threshold
voltage
VCEL
0.6
V
Vout=Vout*0.96 Test EXT pin
frequency
Oscillator frequency
FOSC
300 350 400
Khz
CE ”H”
CE “L”
ICEH
ICEL
Vout=VCE=6V
-0.5
-0.5
0
0.5
0.5
uA
uA
Vout=VCE=6V
0
3.0V<=Vout<=3.9V
4.0V<=Vout<=4.9V
5.0V<=Vout<=6.9V
3.0V<=Vout<=3.9V
4.0V<=Vout<=4.9V
5.0V<=Vout<=6.9V
On(Vlx “L”) side
-21
-35
-41
23
25
31
75
90
EXT “H” output current
EXT “H” output current
IEXTH
mA
mA
IEXTL
Oscillator duty cycle
Efficiency
Duty
70
80
%
%
η
Note :
1. Diode: Schottky type, such as: 1N5817, 1N5819, 1N5822
2. Inductor: 27uH(R<0.5Ω)
3. Output Capacitor: 100uF (Tantalum type)
4. Vout pin filter capacitor: 1nF (Ceramic type)
5. Input capacitor: 47uF
Typical Application
(1) Application with external NMOSFET
Vin
D 1N5817
Vout
L
27uH
EXT
OUT
Cin
47uF
ACE705
GND
Cout
100uF Tan
Rload
CE
Cp
OFF ON
1nF
Fig2
VER 1.2
4
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
(2) Application with external NPN transistor
ACE705
Fig3
Note: R1=330Ω, C1=10nF. (R1 can be calculated by load. If load is light R1’s value can be added. If load is heavy R1’s value can
be smaller. )
Detailed Description
The ACE705 series are boost structure, voltage-type pulse-frequency modulation(PFM) step-up DC-DC
controller. Only four external components are necessary: an inductor, a schottky diode, an output filter
capacitor and a NMOSFET or a NPN transistor. The step-up DC-DC converter, constructed by ACE705,
can be adjusted from 2.5V to 6.0V, 0.1V step. By using the depletion technics, the quiescent current
drawn from power source is lower than 8uA. The high efficiency device consists of resistors for output
voltage detection and trimming, a start-up voltage circuit, an oscillator, a reference circuit, a PFM control
circuit, a switch protection circuit and a driver transistor.
ACE705 integrates PFM control system. This system controls fixed power switch on duty cycle
frequency to stabilize output voltage by calculating results of other blocks which sense input voltage,
output voltage, output current and load conditions. In PFM modulation system, the frequency and pulse
width is fixed. The duty cycle is adjusted by skipping pulses, so that switch on-time is changed based on
the conditions such as input voltage, output current and load. The oscillate block inside ACE705 provides
fixed frequency and pulse width wave.
The reference circuit provides stable reference voltage to output stable output voltage. Because internal
trimming technology is used, the chip output change less than ±2%. At the same time，the problem of
temperature-drift coefficient of output voltage is considered in design, so temperature-drift coefficient of
output voltage is less than 100ppm/℃。
High-gain differential error amplifier guarantees stable output voltage at difference input voltage
and load. In order to reduce ripple and noise, the error amplifier is designed with high band-with.
ACE705 has a drive pin (EXT) for external transistor. So it is possible to load a large output current with
a power transistor and a low saturation voltage. At very light load condition, the switch current and
quiescent current of chip will effect efficiency certainly. So in very light load condition, the efficiency will
drop. Therefore, it is recommended that user use ACE705 in the condition of load current as large as
several tens of mA to several hundreds of mA
VER 1.2
5
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
Selection of the External Components
Thus it can be seen, the inductor, schottky diode and external NMOSFET or NPN transistor.
affect the conversion efficiency greatly. The inductor and the capacitor also have great influence
on the output voltage ripple of the converter. So it is necessary to choose a suitable inductor, a
capacitor, an external NMOSFET or NPN transistor and a right schottky diode, to obtain high
efficiency and low ripple.
Before discussion，we define D≣Vout-Vin / Vout
(1)Inductor Selection
Above all, we should define the minimum value of the inductor that can ensure the boost DC-DC to
operate in the continuous current-mode condition.
Lmin≧D(1-D)2RL / 2f
The above expression is got under conditions of continuous current mode, neglect Schottky diode’s
voltage, ESR of both inductor and capacitor. The actual value is greater that it. If inductor’s value is less
than Lmin，the efficiency of DC-DC converter will drop greatly, and the DC-DC circuit will not be stable.
Secondly, consider the ripple of the output voltage,
ΔI=D‧Vin / Lf
Im ax=Vin / (1-D)2RL + DVin / 2Lf
If inductor value is too small, the current ripple through it will be great. Then the current through diode
and power switch will be great. Because the power switch on chip is not ideal switch, the energy of switch
will improve. The efficiency will fall.
Thirdly，in general, smaller inductor values supply more output current while larger values start up with
lower input voltage and acquire high efficiency.
An inductor value of 3uH to 1mH works well in most applications. If DC-DC converter delivers large
output current (for example: output current is great than 50mA), large inductor value is recommended in
order to improve efficiency. If DC-DC must output very large current at low input supply voltage, small
inductor value is recommended.
The ESR of inductor will effect efficiency greatly. Suppose ESR value of inductor is rL，Rload is load
resistor，then the energy can be calculated by following expression:
Δη≈ RL / Rload (1-D)2
For example: input 1.5V, output is 3.0V, Rload=20Ω, rL=0.5Ω, The energy loss is 10%.
Consider all above，inductor value of 47uH、ESR<0.5Ω is recommended in most applications. Large
value is recommended in high efficiency applications and smaller value is recommended
VER 1.2
6
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
(2)Output Capacitor Selection
Ignore ESR of capacitor，the ripple of output voltage is:
R=ΔVout / Vout=D / Rload Cf
So large value capacitor is needed to reduce ripple. But too large capacitor value will slow down system
reaction and cost will improve. So 100uF capacitor is recommended. Larger capacitor value will be used
in large output current system. If output current is small (<10mA), small value is needed.
Consider ESR of capacitor，ripple will increase：
r'=r+Imax‧RESR / Vout
When current is large, ripple caused by ESR will be main factor. It may be greater than 100mV。The ESR
will affects efficiency and increase energy loss. So low-ESR capacitor (for example: tantalum capacitor) is
recommend or connect two or more filter capacitors in parallel.
(3)Diode Selection
Rectifier diode will affects efficiency greatly，Though a common diode (such as 1N4148) will work well for
light load，it will reduce about 5%~10% efficiency for heavy load，For optimum performance, a Schottky
diode (such as 1N5817、1N5819、1N5822) is recommended.
(4)Input Capacitor
If supply voltage is stable, the DC-DC circuit can output low ripple, low noise and stable voltage without
input capacitor. If voltage source is far away from DC-DC circuit, input capacitor value greater than 10uF
is recommended.
(5)Vout~GND filter Capacitor
Because the chip’s switch current flows from Vout pin, then through the chip into GND pin. Therefore if
the output capacitor’s two pins were not very near the chip’s Vout pin and GND pin, Vout ‘s stable would
be affected. User will found that the output voltage will drop when load grows up if the output capacitor’s
two pin is not very near the chip’s Vout pin and GND pin. In this condition, 1nF ceramic capacitor is
recommended at very near the chip’s Vout pin and GND pin. So in all ACE705 application, two capacitors
are needed to obtain stable output voltage. The 100μF tantalum output capacitor is recommended to
stable output voltage nearby load. The 1nF Vout pin to GND pin ceramic filter capacitor is recommended
to stable chip’s sense voltage.
VER 1.2
7
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
Test Circuits
(1) Output voltage test circuit
ACE705
Fig4
(2) Quiescent current test circuit
ACE705
Fig5
(3) Input Current (no load) test circuit
ACE705
Fig6
(4) Oscillator frequency and duty cycle test circuit
ACE705
Fig7
VER 1.2
8
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
Extend Applications
(1) 12V step-up application
ACE705
Fig8
Note: ACE705’s output voltage is 6V. When the output current is small or no load, the output voltage will be unstable, use the
RZD for flowing the bias current through the zener diode. For step-up application, a diode(for example: 1N4148) is
needed as starter circuit.
(2) Step-down application
ACE705
Fig9
Note: In step-down application, use starter circuit as above. 2.5V Vzener Vout. RST is needed for bias current of zener
≤
≤
diode. This starter circuit also can be used in high voltage step-up application.
VER 1.2
9
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
(3) Flyback step-up/step-down application
ACE705
Fig10
Note: In step-down and step-up/step-down application, starter circuit in fig 8 is need. In step-up application, simpler starter
circuit in fig 9 can be used.
Typical Characteristic
(Recommended operating conditions: L=10uH, Cin=47uF, Cout=100uF, Topt=25℃, unless otherwise noted)
1.Output Voltage VS. Output Current
2.Output Voltage VS. Output Current
ACE705230BN+ Output Voltage VS. Output Current
ACE705240BN+ Output Voltage VS. Output Current
Iout (mA)
Iout (mA)
3.Output Voltage VS. Output Current
4.Efficiency VS. Output Current
ACE705260BN+ Output Voltage VS. Output Current
ACE705230BN+ Efficiency VS. Output Current
Iout (mA)
Iout (mA)
VER 1.2 10
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
5. Efficiency VS. Output Current
6.Efficiency VS. Output Current
ACE705240BN+ Efficiency VS. Output Current
ACE705260BN+ Efficiency VS. Output Current
Iout (mA)
Iout (mA)
7. Ripple VS. Output Current
8.Ripple VS. Output Current
ACE705230BN+ Ripple VS. Output Current
ACE705240BN+ Ripple VS. Output Current
Iout (mA)
Iout (mA)
9. Ripple VS. Output Current
ACE705260BN+ Ripple VS. Output Current
Iout (mA)
VER 1.2 11
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
Packing Information
SOT-23-3
VER 1.2 12
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
Packing Information
SOT-23-5
VER 1.2 13
ACE705
High efficiency, multi-funtion step-up
DC/DC Controller
Technology
Notes
ACE does not assume any responsibility for use as critical components in life support devices or systems
without the express written approval of the president and general counsel of ACE Electronics Co., LTD.
As sued herein:
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and shoes failure to perform when properly used in
accordance with instructions for use provided in the labeling, can be reasonably expected to result in
a significant injury to the user.
2. A critical component is any component of a life support device or system whose failure to perform can
be reasonably expected to cause the failure of the life support device or system, or to affect its safety
or effectiveness.
ACE Technology Co., LTD.
http://www.ace-ele.com/
VER 1.2 14
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