IA2521 is a low-cost integrated synchronous buck-boost converter IC specifically designed for driving camera flash LEDs, both for flash and for flashlight (torch) operation. It can be operated from a single Lithium cell or two alkaline cells, and drives a single LED with high efficiency at up to 1W of continuous power, with pulses up to 3W. The IA2521 device has its torch-mode output current controlled by a resistor to ground, flash-mode current controlled by a resistor to logic, and pulse time controlled by an ENABLE signal. Full flash brightness is reached as quickly as a xenon tube. The IA2521 incorporates spread-spectrum switching to minimize EMI, is self-protected against open-string conditions and thermal overloads, and is available in either an MSOP-8 or a QFN-16 package. 
| Parameter |
Condition |
Min |
Typ |
Max |
Units |
| ITORCH Range |
ITORCH = 1 MΩ to 300 KΩ, if IFLASH Open |
75 |
|
250 |
mA |
| IFLASH Range |
IFLASH = 1 MΩ to 300 KΩ, ITORCH = 300 KΩ |
75 |
|
1000 |
mA |
| IFLASH Rise Time |
ILED 200mA to 1A |
|
85 |
|
µsec |
| Switching Frequency |
|
400 |
500 |
600 |
kHz |
| Input Voltage Range |
|
2.7 |
|
4.5 |
V |
|
 |
- Buck-boost converter for LED camera flash
- Full flash brightness in 100µsec
- High-efficiency synchronous operation, no diodes
- Battery voltage higher or lower than LED voltage
- Flashlight mode
- Spread-spectrum switching for EMI control
- Up to 1W continuous, 3W pulse output power
- 2.5V to 4.5V input voltage range
- Single resistor for each brightness setting
- ENABLE pin for timing
- Self-protected against open string and thermal overload
- Inductor current is automatically current-limited
- 1µA maximum shutdown current
- MSOP-8 or QFN-16 package
|
|
