ACTIVE-SEMI ACT4525 40v/3.5a cv/cc buck converter with usb auto â detect Datasheet

ACT4525
Rev 1.1, December 17th, 2015
40V/3.5A CV/CC Buck Converter with USB Auto –Detect
 Rechargeable Portable Device
 CV/CC regulation DC/DC converter
FEATURES








Pass Apple MFi Test
40V Input Voltage Surge
4.5V-36V Operational Input Voltage
Dual 5.1V Outputs with 1% Accuracy
Up to 3.5A Output Current
2.65A Constant Current Regulation for VOUT1
1.2A Constant Current Regulation for VOUT2
USB Auto-detect Support Apple 2.4A, Samsung
and BC1.2 Devices
Hiccup Mode Protection at Output Short
90% Efficiency at Full Load
0.5mA Low Standby Input Current
5.7V Output Over Voltage Protection
Cord Voltage Drop Compensation
Meet EN55022 Class B Radiated EMI Standard
8kV ESD HBM Protection on DP and DM
SOP-8EP Package








GENERAL DESCRIPTION
ACT4525 is a wide input voltage, high efficiency
step-down DC/DC converter that operates in either
CV (Constant Output Voltage) mode or CC
(Constant Output Current) mode. ACT4525 has
separated output current limits for dual port CLA
applications. With the separated current limits, the
CLA can meet Apple’s MFi standard. ACT4525
provides up to 3.5A output current at 125kHz
switching frequency. ACT4525 builds in USB autodetect algorithms to recognize Apple, Samsung,
and BC1.2 devices to ensure maximum charge
current to attached devices. ACT4525 utilize
adaptive drive technique to achieve good EMI
performance while main 90% efficiency at full load
for mini size CLA designs. ACT4525 also built in
output short circuit protection with hiccup mode.
The average output current is reduced to below
6mA when output is shorted to ground. Other
features include output over voltage protection and
thermal shutdown.
APPLICATIONS
The devices are available in a SOP-8EP package
and require very few external devices for operation.
 Car Charger
 Cigarette Lighter Adaptor (CLA)
V/I Profile
Vout1
5.25V
Typical Application Circuit
5.10V
4.95V
3.20V
4.5V to 40V
CSN2
CSN1
C3
22nF
HSB
SW
IN
ACT4525
C1
47μF
C2
10μF
CSP
GND
DP
DM
D1
SK54L
Rcs2
50mΩ
L1
33μH
C4
C5
10μF 470μF
Rcs1
25mΩ
C6
2.2μF
5.1V/2.4A
Vout
Iout1
5.1V/1A
2.4A
Vout
D-
C7
2.2μF D-
D+
D+
GND
GND
2.9A
Vout2
5.25V
5.10V
4.95V
3.20V
Iout2
1.1A
* Patent Pending
Innovative PowerTM
-1-
1.3A
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
ORDERING INFORMATION
PART NUMBER
OPERATION TEMPERATURE RANGE
PACKAGE
FREQUENCY
PACKING
ACT4525YH-T
-40°C to 85°C
SOP-8EP
125kHz
TAPE & REEL
PIN CONFIGURATION
CSP
1
8
HSB
CSN1
2
7
SW
6
IN
5
DM
ACT4525
CSN2
3
DP
4
GND
EP
SOP-8EP
Top View
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-2-
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
PIN DESCRIPTIONS
PIN
NAME
DESCRIPTION
1
CSP
Voltage Feedback Input. Connect to node of the inductor and output capacitor. CSP,
CSN1 and CSN2 Kevin sensing is recommended.
2
CSN1
Output current sense negative input. Connect to the negative terminal of current
sense resistor for VOUT1.
3
CSN2
Output current sense negative input. Connect to the negative terminal of current
sense resistor for VOUT2.
4
DP
Data Line Positive Input. Connected to D+ of attached portable device data line.
This pin passes 8kV HBM ESD.
5
DM
Data Line Negative Input. Connected to D- of attached portable device data line.
This pin passes 8kV HBM ESD.
6
IN
Power Supply Input. Bypass this pin with a 10μF ceramic capacitor to GND, placed
as close to the IC as possible.
7
SW
Power Switching Output to External Inductor.
8
HSB
High Side Bias Pin. This provides power to the internal high-side MOSFET gate
driver. Connect a 22nF capacitor from HSB pin to SW pin.
9
GND
Ground and Heat Dissipation Pad. Connect this exposed pad to large ground
copper area with copper and vias.
ABSOLUTE MAXIMUM RATINGS
PARAMETER
VALUE
UNIT
-0.3 to 40
V
SW to GND
-1 to VIN +1
V
HSB to GND
VSW - 0.3 to VSW + 7
V
-0.3 to +6
V
46
°C/W
Operating Junction Temperature
-40 to 150
°C
Storage Junction Temperature
-55 to 150
°C
300
°C
IN to GND
CSP, CSN1, CSN2, DP , DM to GND
Junction to Ambient Thermal Resistance
Lead Temperature (Soldering 10 sec.)
: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may
affect device reliability.
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-3-
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
ELECTRICAL CHARACTERISTICS
(VIN = 12V, TA = 25°C, unless otherwise specified.)
Parameter
Input Over Voltage Protection
Symbol
VIN_OVP
Condition
Rising
Min
Typ
Max
Units
40
42
44
V
Input Over Voltage Hysteresis
Input Over Voltage Response Time
Input Under Voltage Lockout (UVLO)
T_VIN_OVP VIN step from 30V to 45V
VIN
Rising
Input UVLO Hysteresis
4
V
250
ns
4.5
V
200
mV
Input Voltage Power Good Deglitch
Time
No OVP
40
ms
Input Voltage Power Good Deglitch
Time
No UVP
10
us
Input Standby Current
Vin=12V, Vout=5.1V, Iload=0
500
uA
Output Voltage Regulation
CSP
Output Over Voltage Protection
(OVP)
5.05
Output rising
Output Over Voltage Deglitch Time
Output Voltage Cord Compensation
5.1
5.15
V
5.7
V
1.0
us
Output current 2.4A
-15%
100
+15%
mV
-10%
3.2
10%
V
Output Under Voltage Protection
(UVP)
VOUT
VOUT falling
UVP Hysteresis
VOUT
VOUT rising
UVP Deglitch Time
VOUT
UVP Blanking Time at Startup
0.2
V
10
us
3.5
ms
CC1
Rcs=25mΩ
2.50
2.65
2.80
A
CC2
Rcs=50mΩ
1.1
1.2
1.3
A
Output Constant Current Limit
Hiccup Waiting Time
4.13
S
5.8
A
Top FET Rdson
70
mΩ
Bottom FET Rdson
4.7
Ω
Top FET Cycle by Cycle Current
Limit
4.5
Maximum Duty Cycle
99
Switching Frequency
-10%
Soft-start Time
Innovative PowerTM
%
125
2.0
-4-
+10%
kHz
ms
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
ELECTRICAL CHARACTERISTICS
(VIN = 12V, TA = 25°C, unless otherwise specified.)
Parameter
Symbol
Condition
Min
Out Voltage Ripples
Cout=470uF/22uF ceramic
Line Transient Response
Input 12V-40V-12V with 1V/us
slew rate, Vout=5V, Iload=0A
and 2.4A
4.75
80mA-1.0A-80mA load with
0.1A/us slew rate
4.9
Load Transient Response
Vout=5V
Typ
Max
80
5.15
Units
mV
5.25
V
5.4
V
Thermal Shut Down
160
°C
Thermal Shut Down Hysteresis
30
°C
8
kV
ESD of DP, DM
Innovative PowerTM
HBM
-5-
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
FUNCTIONAL BLOCK DIAGRAM
HSB
VIN
PWM
Controller
UVLO
70mΩ
USB
Auto
Detect
Driver
DP
OVP
Current Sense
and Control
CSP
CSN1
SW
4.7Ω
DM
CSN2
GND
FUNCTIONAL DESCRIPTION
In some applications, the
increased with output current
potential voltage drop across
compensation is based on the
resistance.
Output Current Sensing and Regulation
Sense resistor is connected to CSP and CSN1,
CSN2 respectively. The sensed differential voltages
are compared with interval references to regulate
currents. CC loop and CV loop are in parallel. The
current loop response is allowed to have slower
response compared to voltage loop. However,
during current transient response, the inductor
current overshoot/undershoot should be controlled
within +/-25% to avoid inductor saturation.
output voltage is
to compensate the
output cable. The
high side feedback
The compensation voltage is derived as:
ΔVout = (VCSP-VCSN)*K
This voltage difference could be added on the
reference or turning the (VCSP-VCSN) voltage into a
sink current at FB pin to pull Vout higher than
programmed voltage.
Cycle-by-Cycle Current Control
The conventional cycle-by-cycle peak current mode
is implemented with high-side FET current sense.
The cord compensation loop should be very slow to
avoid potential disturbance to the voltage loop. The
voltage loop should be sufficiently stable on various
cord compensation setting.
Input Over Voltage Protection
The converter is disabled if the input voltage is
above 42V (+/-2V). Device resumes operation
automatically 40ms after OVP is cleared.
Thermal Shutdown
If the TJ increases beyond 160°C, ACT4525 goes
into HZ mode and the timer is preserved until T J
drops by 30°C.
Output Over Voltage Protection
Device stops switching when output over-voltage is
sensed, and resumes operation automatically when
output voltage drops to OVP - hysteresis.
Output Under-Voltage Protection /
Hiccup Mode
There is a under voltage protection (UVP)
threshold. If the UVP threshold is hit for 10us, an
over current or short circuit is assumed, and the
converter goes into hiccup mode by disabling the
converter and restarts after hiccup waiting period.
Cord Compensation
Innovative PowerTM
-6-
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
APPLICATIONS INFORMATION
Inductor Selection
Output Capacitor
The inductor maintains a continuous current to the
output load. This inductor current has a ripple that is
dependent on the inductance value.
Higher inductance reduces the peak-to-peak ripple
current. The trade off for high inductance value is
the increase in inductor core size and series
resistance, and the reduction in current handling
capability. In general, select an inductance value L
based on ripple current requirement:
L=
VOUT ×(VIN _VOUT )
VIN fSW ILOADMAX K RIPPLE
The output capacitor also needs to have low ESR to
keep low output voltage ripple. The output ripple
voltage is:
VRIPPLE  I OUTMAX K RIPPLE RESR 
(1)
With a selected inductor value the peak-to-peak
inductor current is estimated as:
VOUT ×(VIN _VOUT )
L ×VIN ×fSW
2
28  f SW LCOUT
(5)
Where IOUTMAX is the maximum output current,
KRIPPLE is the ripple factor, RESR is the ESR of the
output capacitor, fSW is the switching frequency, L is
the inductor value, and COUT is the output
capacitance. In the case of ceramic output
capacitors, RESR is very small and does not
contribute to the ripple. Therefore, a lower
capacitance value can be used for ceramic type. In
the case of tantalum or electrolytic capacitors, the
ripple is dominated by RESR multiplied by the ripple
current. In that case, the output capacitor is chosen
to have sufficiently low ESR.
Where VIN is the input voltage, VOUT is the output
voltage, fSW is the switching frequency, ILOADMAX is
the maximum load current, and KRIPPLE is the ripple
factor. Typically, choose KRIPPLE = 30% to
correspond to the peak-to-peak ripple current being
30% of the maximum load current.
ILPK _ PK =
VIN
For ceramic output capacitor, typically choose a
capacitance of about 22µF. For tantalum or
electrolytic capacitors, choose a capacitor with less
than 50mΩ ESR. An 330µF or 470µF electrolytic
capacitor is recommended.
(2)
The peak inductor current is estimated as:
Rectifier Schottky Diode
1
ILPK = ILOADMAX + ILPK _ PK
(3)
2
The selected inductor should not saturate at ILPK.
The maximum output current is calculated as:
LLIM is the internal current limit.
Use a Schottky diode as the rectifier to conduct
current when the High-Side Power Switch is off.
The Schottky diode must have current rating higher
than the maximum output current and a reverse
voltage rating higher than the maximum input
voltage. Further more, the low forward voltage
Schottky is preferable for high efficiency and
smoothly operation.
Input Capacitor
Current Sense Resistor
The input capacitor needs to be carefully selected
to maintain sufficiently low ripple at the supply input
of the converter. A low ESR capacitor is highly
recommended. Since large current flows in and out
of this capacitor during switching, its ESR also
affects efficiency.
The traces leading to and from the sense resistor
can be significant error sources. With small value
sense resistors, trace resistance shared with the
load can cause significant errors. It is
recommended to connect the sense resistor pads
directly to the CSP and CSN pins using “Kelvin” or
“4-wire” connection techniques as shown below.
IOUTMAX = ILIM _
1
I _
2 LPK PK
(4)
The input capacitance needs to be higher than
10µF. The best choice is the ceramic type.
However, low ESR tantalum or electrolytic types
may also be used provided that the RMS ripple
current rating is higher than 50% of the output
current. The input capacitor should be placed close
to the IN and GND pins of the IC, with the shortest
traces possible. In the case of tantalum or
electrolytic types, a ceramic capacitor is
recommended to parallel with tantalum or
electrolytic capacitor, which should be placed right
next to the IC.
Innovative PowerTM
PCB Load
Trace
Kevin Sense
Traces
-7-
Sense
Resistor
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
APPLICATIONS INFORMATION
PC Board Layout Guidance
When laying out the printed circuit board, the
following checklist should be used to ensure proper
operation of the IC.
1) Arrange the power components to reduce the
AC loop size consisting of CIN, VIN pin, SW pin
and the Schottky diode.
2) Place input decoupling ceramic capacitor CIN as
close to VIN pin as possible. C IN is connected
power GND with vias or short and wide path.
3) Use “Kelvin” or “4-wire” connection techniques
from the sense resistor pads directly to the CSP
and CSN1, CSN2 pins.
4) Use copper plane and thermal vias for GND for
best heat dissipation and noise immunity.
5) Use short trace connecting HSB-CHSB-SW loop.
6) SW pad is noise node switching from VIN to
GND. It should be isolated away from the rest
of circuit for good EMI and low noise operation.
Innovative PowerTM
-8-
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
Typical Application Circuit for 5V/3.4A Car Charger
CSN2
4.5V to 40V
C1
47μF
IN
C2
10μF
CSN1
U1
ACT4525
GND
DP
C3
22nF
HSB
SW
L1
33μH
CSP
DM
Rcs2
50mΩ
D1
SK54L
C4
C5
10μF 470μF
Rcs1
25mΩ
C6
2.2μF
5.1V/2.4A
Vout
5.1V/1A
Vout
D-
C7
2.2μF D-
D+
D+
GND
GND
BOM List for 5V/3.4A Car Charger
ITEM REFERENCE
DESCRIPTION
MANUFACTURER
QTY
1
U1
IC, ACT4525, SOP-8EP
Active-Semi
1
2
C1
Capacitor, Electrolytic, 47µF/35V
Murata, TDK
1
3
C2
Capacitor, Ceramic, 10µF/25V, 1206, SMD
Murata, TDK
1
4
C3
Capacitor, Ceramic, 22nF/25V, 0603, SMD
Murata, TDK
1
5
C4
Capacitor, Ceramic, 10µF/10V, 1206, SMD
Murata, TDK
1
6
C5
Capacitor, Electrolytic, 470µF/10V
Murata, TDK
1
7
C6,C7
Capacitor, Ceramic, 2.2µF/10V, 0805, SMD
Murata, TDK
2
8
L1
Inductor, 33µH, 4.5A, 20%,
9
D1
Diode, Schottky, 40V/5A, SK54L
Panjit
1
10
Rcs1
Chip Resistor, 25mΩ, 1206, 1/2W, 1%
SART
1
11
Rcs2
Chip Resistor, 50mΩ, 1206, 1/2W, 1%
SART
1
Innovative PowerTM
1
-9-
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
TYPICAL PERFORMANCE CHARACTERISTICS
(Schematic as show in typical application circuit, Ta = 25°C, unless otherwise specified)
Output1 CC/CV Curve
Efficiency vs. Load current
5.0
Output Voltage (V)
Efficiency (%)
90
85
VIN =24V
80
ACT4525-002
VIN =12V
95
6.0
ACT4525-001
100
75
70
65
VIN =24V
4.0
VIN =12V
3.0
2.0
1.0
60
0
500
1000
1500
2000
2500
3000
0
3500
0
500
Load Current (mA)
1500
2000
2500
3000
Output Current (mA)
Output Over Voltage (5V Vout)
Start up into CC Mode
ACT4525-004
ACT4525-003
CH1
1000
CH1
VOUT = 5.1V
RLORD = 1.5Ω
IOUT = 2.65A
VIN = 12V
CH2
CH2
CH3
CH1: VIN, 10V/div
CH2: VOUT, 2V/div
CH3: IOUT, 2A/div
TIME: 400µs/div
CH1: VOUT, 1V/div
CH2: SW, 10V/div
TIME: 1ms/div
Load Transient (80mA-1A-80mA)
Vin=12V, Vout=5V
Load Transient (1A-2.4A-1A)
Vin=12V, Vout=5V
CH2
ACT4525-006
ACT4525-005
CH1
CH1
CH2
CH1: VOUT, 100mV/div
CH2: IOUT, 1A/div
TIME: 400us//div
Innovative PowerTM
CH1: VOUT, 200mV/div
CH2: IOUT, 1A/div
TIME: 400us//div
- 10 -
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Copyright © 2015 Active-Semi, Inc.
ACT4525
Rev1.1, December 17th, 2015
PACKAGE OUTLINE
SOP-8EP PACKAGE OUTLINE AND DIMENSIONS
E
b
e
D
D1
SYMBOL
E2
A1
E1
A2
A
L
θ
c
DIMENSION IN
MILLIMETERS
DIMENSION IN
INCHES
MIN
MAX
MIN
MAX
A
1.350
1.727
0.053
0.068
A1
0.000
0.152
0.000
0.006
A2
1.350
1.550
0.053
0.061
b
0.330
0.510
0.013
0.020
c
0.170
0.250
0.007
0.010
D
4.700
5.100
0.185
0.200
D1
3.202
3.402
0.126
0.134
E
3.734
4.000
0.147
0.157
E1
5.800
6.200
0.228
0.244
E2
2.313
2.513
0.091
0.099
e
1.270 TYP
0.050 TYP
L
0.400
1.270
0.016
0.050
θ
0°
8°
0°
8°
Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each
product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use
as critical components in life-support devices or systems. Active-Semi, Inc. does not assume any liability arising out of
the use of any product or circuit described in this datasheet, nor does it convey any patent license.
Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact
[email protected] or visit http://www.active-semi.com.
®
is a registered trademark of Active-Semi.
Innovative PowerTM
- 11 -
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Copyright © 2015 Active-Semi, Inc.
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