ACE729C [ACE]
4A, 16V High Efficiency Synchronous Step-Down Converter;
| 型号： | ACE729C |
| 厂家： | 
ACE TECHNOLOGY CO., LTD. |
| 描述： | 4A, 16V High Efficiency Synchronous Step-Down Converter |
| 文件： | 总8页 (文件大小：448K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
ACE729C
4A, 16V High Efficiency Synchronous Step-Down Converter
Description
The ACE729C is a wide input range, high-efficiency, DC-to- DC step-down switching regulator, capable
of delivering up to 4A of output current. Current mode PWM control allows the use of small external
components, such as ceramic input and output caps, as well as small inductors, while still providing low
output ripples. On top of the integrated internal synchronous rectifier that eliminates external Schottky
diode, ACE729C also employs a proprietary control scheme that switches the device into a power save
mode during light load, thereby extending the range of high efficiency operation. Therefore, ACE729C is a
much superior solution in comparison to other competitions in terms of efficiency and cost. Overall,
ACE729C is a highly efficient and robust solution for DC-DC step-down applications that requires wide
input ranges.
Features
Wide Input Operating Range from 4.5V to 16V
High Efficiency: Up to 95% at Light Load
Capable of Delivering 4A
No external Schottky Diode Needed
Inductor Short Circuit Protection
Current Mode Control
0.923V Reference for Low Output Voltages
Logic Control Shutdown
Thermal Shutdown and UVLO
Available in ESOP8 package
Application
LCD TVs
Notebook computers
FPGA power supplies
LED drivers
Absolute Maximum Ratings
Parameter
Value
Input Voltage
SW.EN Voltage
-0.3V to 17V
-0.3V to VIN +0.3V
-0.3V to SW+6V
-0.3V to 6V
BST Voltage
FB Voltage
SW to ground current
Ambient Temperature(Ta)
Storage Temperature(Ts)
Internally limited
-40°C - 85°C
-55°C - 150°C
Note: Exceed these limits to damage to the device. Exposure to absolute maximum rating conditions may
affect device reliability.
VER 1.1
1
ACE729C
4A, 16V High Efficiency Synchronous Step-Down Converter
Packaging Type
ESOP-8
Pinout Description
Pin NO.
Name
BST
VIN
SW
Description
High side power transistor gate drive boost input.
Power input. Bypass with a 10uF~22uF ceramic capacitor to GND.
Power switching node to connect inductor.
Ground.
1
2
3
4
5
6
7
8
GND
FB
Feedback input with reference voltage set to 0.923V.
No connection
NC
EN
Enable input. Set this pin to high level to enable the part, low level to disable.
No connection
NC
Ordering information
ACE729CXX+ H
Halogen - free
Pb - free
IM: ESOP-8
Typical Application
VER 1.1
2
ACE729C
4A, 16V High Efficiency Synchronous Step-Down Converter
Electrical Characteristics
Parameter
Conditions
Min
Typ
Max Unit
Input Voltage Range
4.2
16
V
V
UVLO Threshold
4.1
0.8
VEN= 2.0V, VFB = 1.1V
VEN = 0V or VEN = GND
4.2V≤VIN ≤16V
Supply Current in Operation
Supply Current in Shutdown
Regulated Feedback Voltage
High-side Switch On Resistance
Low-side Switch On Resistance
High-side Switch Leakage Current
Upper Switch Current Limit
Oscillation Frequency
mA
uA
V
1
0.904 0.923 0.942
VBST-SW = 5V
120
60
m Ω
m Ω
uA
A
VIN = 5V
VEN = 0V, VSW = 0V
Minimum Duty Cycle
0
10
6
500
92
KHz
%
VFB= 0.8V
Maximum Duty Cycle
Minimum On Time
100
160
ns
Thermal Shutdown
°C
VER 1.1
3
ACE729C
4A, 16V High Efficiency Synchronous Step-Down Converter
Typical Performance Characteristics
(L=4.7uH, Cin=22uF, Cout=22uF, TA=25℃, unless otherwise stated)
VER 1.1
4
ACE729C
4A, 16V High Efficiency Synchronous Step-Down Converter
Functional Decriptions
Loop Operation
The ACE729C is a wide input range, high-efficiency, DC-to- DC step-down switching regulator, capable of
delivering up to 4A of output current, integrated with a 120/60m synchronous MOSFET pair, eliminating
the need for external diode. It uses a PWM current-mode control scheme. An error amplifier integrates
error between the FB signal and the internal reference voltage. The output of the integrator is then
compared to the sum of a current-sense signal and the slope compensation ramp. This operation
generates a PWM signal that modulates the duty cycle of the power MOSFETs to achieve regulation for
output voltage.
Current Limit
There is a cycle-by-cycle current limit on the high-side MOSFET of 6A (typ). When the current flowing out
of SW exceeds this limit, the high-side MOSFET turns off and the synchronous rectifier turns on. Unlike
the traditional method of current limiting by limiting the voltage at the compensation pin, which usually has
large variation due to duty cycle variance, this type of peak current limiting scheme provides a relatively
more accurate limit for output current, thereby lowering the requirements for system design.
Light Load Operation
Traditionally, a fixed constant frequency PWM DC-DC regulator always switches even when the output
load is small. When energy is shuffling back and forth through the power MOSFETs, power is lost due to
the finite RDSONs of the MOSFETs and parasitic capacitances. At light load, this loss is prominent and
efficiency is therefore very low. ACE729C employs a proprietary control scheme that improves efficiency
in this situation by enabling the device into a power save mode during light load, thereby extending the
range of high efficiency operation.
VER 1.1
5
ACE729C
4A, 16V High Efficiency Synchronous Step-Down Converter
PCB Layout Recommendation
The device’s performance and stability are dramatically affected by PCB layout. It is recommended to
follow these general guidelines shown as below:
1. Place the input capacitors and output capacitors as close to the device as possible. The traces which
connect to these capacitors should be as short and wide as possible to minimize parasitic inductance
and resistance.
2. Place feedback resistors close to the FB pin.
3. Keep the sensitive signal (FB) away from the switching signal (SW).
4. The exposed pad of the package should be soldered to an equivalent area of metal on the PCB. This
area should connect to the GND plane and have multiple via connections to the back of the PCB as
well as connections to intermediate PCB layers. The GND plane area connecting to the exposed pad
should be maximized to improve thermal performance.
5. Multi-layer PCB design is recommended.
VER 1.1
6
ACE729C
4A, 16V High Efficiency Synchronous Step-Down Converter
Packing Information
ESOP-8
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
A1
A2
b
1.350
0.100
1.350
0.330
0.170
4.700
3.800
5.800
1.750
0.250
1.550
0.510
0.250
5.100
4.000
6.200
0.053
0.004
0.053
0.013
0.006
0.185
0.150
0.228
0.069
0.010
0.061
0.020
0.010
0.200
0.157
0.244
c
D
E
E1
e
1.270 (BSC)
0.050 (BSC)
L
0.400
0°
1.270
8°
0.016
0°
0.050
8°
θ
VER 1.1
7
ACE729C
4A, 16V High Efficiency Synchronous Step-Down Converter
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 1.1
8
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