AS3630
8A Supercap Flash Driver
General Description
The AS3630 is an inductive high efficient 4MHz dual DCDC step
up converter with several sources. It supports the charging of a
Supercap, its voltage balancing and a highly efficient DCDC step
up from the Supercap to the LED and from VIN to the LED to
power the flash LED with up to 8A. The AS3630 supports the
pre-charging of the Supercap (to VIN) to reduce the startup time
for the flash without reducing the lifetime of the Supercap.
The system concept supports an immediate torch function
without first charging the Supercap.
The AS3630 includes flash timeout, over- undervoltage,
overtemperature and LED short circuit protection.
The AS3630 is controlled by an I²C interface for adjustment of
the currents and timings, set the end of charge voltage and
measure the Supercap and LED parameters through the internal
ADC. A dedicated TXMASK/TORCH input can be used for a torch
button -or- reducing the battery current if a RF PA is operated
at the same time (TX Masking). A hardware enable pin -ON can
be used as a reset input.
The AS3630 is available in a space-saving WL-CSP 5x5 balls
package measuring only 2.5x2.5x0.6mm and operates over the
-30ºC to +85ºC temperature range.
Figure AS3630 – 1:
Key Benefits and Features
Benefits
Reduce Supercap size
Instantaneous Torch operation for improved user
experience
Tiny external coils
Features
Dual high efficiency boost converter with soft start
allows small coils
Immediate Torch functions with charging of the
Supercap
4MHz fixed frequency DCDC
10bit ADC converter for system monitoring with
Protection functions:
Automatic Flash Timeout timer to protect the LED
Overvoltage and undervoltage Protection
LED (NTC) and device Overtemperature Protection
LED short/open circuit protection
Flash LED(s) cathode connected to ground:
System Safety
Improved thermal performance (ground = heat sink)
8A Supercap Flash Driver
AS3630 – 1
Benefits
Features
LED currents (fully adjustable by interface)
• 8A for 33ms and 6A for 120ms (Flash), 2.9mA -
272mA for torch
• 1mA-8mA indicator current
I²C Interface with Interrupt output and ON pin
Fine control of current to fit to applications
Full control and hardware ON pin for easier system
integration
Applications
Figure AS3630 – 2:
Typical Operating Circuit
The device is ideal for Flash/Torch for mobile phones, DSC and
Tablets.
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Typical Operating Circuit:
Shows the main function blocks of the AS3630.
AS3630 – 2
8A Supercap Flash Driver
Pin Assignment
Figure AS3630 – 3:
Pin Assignments (Top View)
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8A Supercap Flash Driver
AS3630 – 3
Pin Description
Figure AS3630 – 4:
Pin Description
Pin Number
A1
Pin Name
STROBE
Description
Digital input with pulldown to control strobe time for flash
function
1
LED temperature sensor input - connect to NTC and connect its
GND with a separate ground wire to AGND
Digital input, open drain output - serial data input/output for I²C
interface (needs external pullup resistor)
Digital Input
3
- serial clock input for I²C mode
Analog ground - connect to ground (GND)
Supercap connection
Indicator LED current source output
Function 1
• “TXMASK” Connect to RF power amplifier enable signal -
reduces currents during flash to avoid a system shutdown
due to parallel operation of the RF PA and the flash driver.
Function 2
• “TORCH” Operate torch current level without using the I²C
interface to operate the torch without need to start a
camera processor (if the I²C is connected to the camera
processor.
Digital Input active high - a logic 1 enables of the AS3630; a logic
0 resets the AS3630
Positive supply voltage input - connect to supply and make a
short connection to input capacitor CVIN and to coil L
DCDC1
Supercap balance pin - balances both single capacitors inside the
Supercap
DCDC converter 2 switching node - make a short connection to
the coil L
DCDC2
and connect all SW2 pins together on top plane
Power ground - connect to ground (GND) and connect all PGND
pins together on top plane
Open drain interrupt output - active low (needs external pullup
resistor)
DCDC converter 1 and 2 output capacitor - make a short
connection to CVOUT1 and connect all VDCDC pins together as
short as possible
A2
A3
A4
A5
B1
B2
NTC
SDA
2
SCL
2
AGND
VSUPERCAP
IND_OUT
B3
TXMASK/TORCH
B4
ON
B5
VIN
C1
BAL
C2
SW2
C3
C4
PGND
INT
C5
VDCDC
AS3630 – 4
8A Supercap Flash Driver
Pin Number
D1
Pin Name
VDCDC
Description
DCDC converter 1 and 2 output capacitor - make a short
connection to CVOUT1 and connect all VDCDC pins together as
short as possible
DCDC converter 2 switching node - make a short connection to
the coil L
DCDC2
and connect all SW2 pins together on top plane
Power ground - connect to ground (GND) and connect all PGND
pins together on top plane
DCDC converter 1 switching node - make a short connection to
the coil L
DCDC1
and connect all SW1 pins together on top plane
Flash LED current source output and connect all LED_OUT pins
together on top plane
DCDC converter 1 and 2 output capacitor - make a short
connection to CVOUT1 and connect all VDCDC pins together as
short as possible
DCDC converter 2 switching node - make a short connection to
the coil L
DCDC2
and connect all SW2 pins together on top plane
Power ground - connect to ground (GND) and connect all PGND
pins together on top plane
DCDC converter 1 switching node - make a short connection to
the coil L
DCDC1
and connect all SW1 pins together on top plane
Flash LED current source output and connect all LED_OUT pins
together on top plane
D2
SW2
D3
PGND
D4
SW1
D5
LED_OUT
E1
VDCDC
E2
SW2
E3
PGND
E4
SW1
E5
LED_OUT
1. Application Information: The pin STROBE is usually connected directly to the camera processor.
2. When SCL and SDA exchanged, the AS3630 uses a different I²C address and the functionality of SCL/SDA is also exchanged - see
“I²C Address
Selection” on page 43.
3. Only input: The AS3630 does not perform clock stretching.
8A Supercap Flash Driver
AS3630 – 5
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