A8732 Datasheet, PDF (1/20 Pages) Allegro MicroSystems – Ultra Small Mobile Phone Xenon Photoflash Capacitor Charger with IGBT Driver

A8732
Ultra Small Mobile Phone Xenon Photoflash
Capacitor Charger with IGBT Driver
Features and Benefits
▪ Ultra small 2 × 2 DFN/MLP-8 package
▪ Low quiescent current draw (0.5 μA max. in shutdown mode)
▪ Primary-side output voltage sensing; no resistor divider required
▪ Adjustable switch peak current limit up to 1.5 A with
single-wire programming through the CHARGE pin
▪ 1V logic (V_HI(min)) compatibility
▪ Integrated IGBT driver with internal gate resistors
▪ Optimized for mobile phone, 1-cell Li+ battery applications
▪ Zero-voltage switching for lower loss
▪ >75% efficiency
▪ Charge complete indication
▪ Integrated 50 V DMOS switch with self-clamping
protection
Package: 8-pin DFN/MLP (suffix EE)
Description
The Allegro^® A8732 is a Xenon photoflash charger IC designed
to meet the needs of ultra low power, small form factor cameras,
particularly camera phones. By using primary-side voltage
sensing, the need for a secondary-side resistive voltage divider
is eliminated. This has the additional benefit of reducing leakage
currents on the secondary side of the transformer. To extend
battery life, the A8732 features very low supply current draw
(0.5 μA max in shutdown mode). The switch current limit can
be programmed from 0.45 to 1.5 A, in 16 steps with single wire
interface, through the CHARGE pin.
The IGBT driver also has internal gate resistors for minimum
external component count. The charge and trigger voltage
logic thresholds are set at 1 V_HI(min) to support applications
implementing low-voltage control logic.
The A8732 is available in an 8-contact 2 mm × 2 mm
DFN/MLP package with a 0.60 maximum overall package
height, and an exposed pad for enhanced thermal performance.
It is lead (Pb) free with 100% matte tin leadframe plating.
Not to scale
2 mm × 2 mm, 0.60 mm height
VIN_VDRV
C2
CHARGE
TRIG
Typical Applications
Battery Input ⁺
2.3 to 5.5 V
C1
VBAT
VOUT Detect
SW
Control
Block
I_SW sense
C_OUT
100F
315 V
VPULLUP
DONE
100 kΩ
DONE
V_{IN_VDRV}
IGBT Driver
IGBT Gate
GATE
VIN_VDRV
C2
CHARGE
TRIG
Battery Input ⁺
1.5 to 5.5 V
C1
VBAT
VOUT Detect
SW
Control
Block
I_SW sense
C_OUT
100F
315 V
VPULLUP
DONE
100 kΩ
DONE
V_{IN_VDRV}
IGBT Driver
IGBT Gate
GATE
GND
GND
(A)
(B)
Figure 1. Typical applications: (A) with single battery supply and (B) with separate bias supply
8732-DS