ACE719E - ACE Technology Co., LTD.

ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
Description
The ACE719E is a high efficiency synchronous step-up converter that can provide up to 3W of power to
a boosted output from a low voltage source. Unlike most step-up converter, not only it starts up at a very
low input voltage as low as 0.85V, it also incorporates circuits that disconnect the input from output,
during shutdown, short-circuit, output current overloading, or other events when output is higher than
the input. This eliminates the need for an external MOSFET and its control circuitry to disconnect the input
from output, and provides robust output overload protection.
The ACE719E starts up from a voltage as low as 0.85V making it ideal for applications with single-cell or
two-cell alkaline, NiCd, and NiMh batteries. A switching frequency of 2MHz minimizes solution footprint by
allowing the use of tiny and low profile inductors and ceramic capacitors. An internal synchronous
MOSFET provides highest efficiency and with a current mode control that is internally compensated,
external parts count is reduced to minimal.
Features












Output Disconnect
Short-circuit Protection
3W Output Power
Output to Input Reversed Current Protection
0.85V Low Start-up Voltage
VIN range from 0.6V to 4.5V
Up to 96% Efficiency
40μA No load IQ and light load PFM Mode
Internal Synchronous Rectifier
Current Mode control
Logic Control Shutdown and Thermal shutdown
DFN2x2-6 Package
Application




USB OTG for MIDs, Smartphones
Mobile back-up Battery Chargers
Alkaline, NiCd, and NiMh batteries applications
USB powered devices
VER 1.2
1
ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
Absolute Maximum Ratings
(Note: Exceeding these limits may damage the device. Exposure to absolute maximum rating conditions for long periods may
affect device reliability.)
Parameter
Value
SW Voltage
-0.3V~5.5V
All Other PIN Voltages
-0.3V~5V
SW to ground current
Internally limited
Operating Temperature Range
-40℃~85℃
Storage Temperature Range
-55℃~150℃
Thermal Resistance
DFN2x2-6
ΘJA
80
ΘJC
30
℃/W
Packaging Type
DFN2x2-6
PIN #
NAME
DESCRIPTION
1
EN
Enable pin for the IC. Drive this pin high to enable the part, low to disable.
FB
Feedback Input. Connect an external resistor divider from the output to FB
and GND to set VOUT
OUT
Output pin. Bypass with a 22μF or larger ceramic capacitor closely between
this pin and GND
GND
Ground Pin
SW
Inductor Connection.Connect an inductor Between SW and the regulator
output.
IN
Input Supply Voltage. Bypass with a 4.7μF ceramic capacitor to GND
2
3
4
5
6
VER 1.2
2
ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
Ordering information
ACE719E XX + H
Halogen - free
Pb - free
MN : DFN2x2-6
Typical Application
Efficiency Vs lOUT
lOUT(A)
Block Diagram
VER 1.2
3
ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
Electrical Characteristics
(VIN = 1.8V, VOUT = 3.3V, unless otherwise specified. Typical values are at TA = 25℃.)
Parameter
Conditions
Min
Minimum Input Voltage
Typ
Max
0.6
Startup Voltage
IOUT=0A
FB Feedback Voltage
VOUT =2.1 to 5V
0.582
Units
V
0.85
1.1
V
0.6
0.618
V
50
nA
5
V
FB Input Current
Output Voltage Range
External divider
Quiescent Current at IN
VFB=0.7V
40
Shutdown Supply Current at IN
VEN=GND
0.5
5
μA
Switching Frequency
VIN<4.3V
2
2.4
MHz
Maximum Duty Cycle
2.1
1.2
μA
90
%
NMOS Switch On Resistance
ISW =100mA
0.15
0.35
Ω
PMOS Switch On Resistance
ISW =100mA
0.15
0.35
Ω
NMOS Switch Current Limit
1.2
Start-up Current Limit
Output to Input Reverse
Leakage Current
SW Leakage Current
VEN=GND, Measure at IN
pin
VOUT=5V,VSW=0 or 5V,
VEN=GND
1.5
A
0.5
A
0.1
EN Input Current
0.1
EN Input Low Voltage
EN Input High Voltage
Thermal Shutdown
0.6
Rising, Hysteresis=10°C
5
μA
10
μA
1
μA
0.3
V
V
165
℃
VER 1.2
4
ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
Typical Characteristics
(Typical values are at TA = 25℃ unless otherwise specified.)
Efficiency Vs lOUT
Efficiency Vs lOUT
lOUT(A)
lOUT(A)
Efficiency Vs VIN
VOUT Vs VIN
VIN(V)
VIN(V)
VOUT Vs lOUT
No Load la Vs VIN
lOUT(A)
VIN(V)
Efficiency Vs lOUT
lOUT(A)
Maximum lOUT Vs vin
VIN(V)
Frequency Vs VIN
VIN(V)
VER 1.2
5
ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
Heavy load Switching Waveform
VIN=1.8V VOUT=3.3V lOUT=500mA
500ns/div
Short-Circuit Recovery
VIN=3V VOUT=3.3V
500ns/div
Load Transient Response
VIN=3V VOUT=3.3V lOUT=0.1A to 0.5A
1ms/div
Light load Switching Waveform
VIN=1.8V VOUT=3.3V lOUT=10mA
100ms/div
Short-Circuit Response
VIN=3V VOUT=3.3V
200μs/div
Star-Up Waveform
VIN=3.0V VOUT=3.3V lOUT=500mA
Shut Down Waveform
VIN=3.0V VOUT=3.3V lOUT=500mA
5ms/div
5ms/div
Load Transient Response
VIN=3V VOUT=3.3V lOUT=0.1A to 1A
Line Transient Response
VOUT=3.3V lOUT =100mA VIN=1.2V to 3V
1ms/div
2ms/div
VER 1.2
6
ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
FUNCTIONAL DECRIPTIONS
Loop Operation
The ACE719E is a wide input range, high-efficiency, DC-to-DC step-up switching regulator, capable of
delivering up to 3W of output power, integrated with a 150mΩ high side MOSFET and 150 mΩ
synchronous rectifier. 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.
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. ACE719E 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.
Short-Circuit Protection
Unlike most step-up converters, the ACE719E allows for short circuits on the output. In the event of a
short circuit, the device first turns off the NMOS when the sensed current reaches the current limit. After
VOUT drops below VIN the device then enters a linear charge period with the current limited same as with
the start-up period. In addition, the thermal shutdown circuits disable switching if the die temperature rises
above 165°C.
Down Mode (VIN>VOUT) Operation
The ACE719E will continue to supply the output voltage even when the input voltage exceeds the output
voltage. Since the PMOS no longer acts as a low-impedance switch in this mode, power dissipation
increases within the IC to cause a sharp drop in efficiency. Limit the maximum output current to maintain
an acceptable junction temperature.
VER 1.2
7
ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
5V APPLICATIONS
When output voltage is programmed to above 4.5V, in order to maintain an acceptable peak voltage at
SW, a small parallel capacitor snubber between SW and OUT is necessary, and an output cap of greater
than 44μF is also required as shown in below figure.
VER 1.2
8
ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
Packing Information
DFN2x2-6
SYMBOL
A
A1
b
c
D
D2
e
Nd
E
E2
L
h
MIN
0.70
0.25
0.18
1.95
1.00
1.95
0.50
0.25
0.10
MILLIMETER
NOM
0.75
0.02
0.30
0.20
2.00
0.65BSC
1.30BSC
2.00
0.30
0.15
MAX
0.80
0.05
0.35
0.25
2.05
1.45
2.05
0.85
0.40
0.20
VER 1.2
9
ACE719E
3W, 0.85V Startup Voltage, Synchronous Step-Up Converter
with Real-Shutdown and Short-Circuit Protection
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
10