The LT1932 is a constant-current DC/DC LED driver from LT company. It has a working frequency of 1.2MHz. The LED current can be adjusted by an external resistor. Even when the input voltage is higher than the LED voltage, the LED current can still be accurately regulated.
The LT1932 is a fixed‑frequency step‑up DC/DC converter designed to operate as a constant‑current source for driving white LEDs. It accepts an input voltage from 1 V to 10 V and regulates LED current directly, making it suitable for battery‑powered devices such as cellular phones, handheld computers, digital cameras and MP3 players. The device uses a 1.2 MHz switching frequency, allowing the use of very small inductors and capacitors to keep the footprint low.
Key features include up to 80 % efficiency, shutdown capability with less than 1 µA quiescent current, and a thin‑SOT package only 1 mm high. The datasheet provides detailed electrical characteristics, pin functions, recommended external components, and several methods for dimming the LED output, including PWM, filtered PWM, logic‑level control, and DC‑voltage control.
| Minimum Input Voltage | 1 V |
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The LT1932 operates with an input voltage from 1 V up to 10 V.
For example, the Panasonic ELJEA4R7 4.7 µH inductor (180 mΩ, 2.2 mm height) is recommended.