The TS19370 is a step-up DC/DC converter specifically designed to drive white LEDs with a constant current. The device can drive 2 ~ 9 LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The output capacitor can be as small as 0.22µF, saving space versus alternative solutions. A low 95mV feedback voltage minimizes power loss for better efficiency. Additional feature include over output voltage limiting when LEDs are disconnected. The TS19370 switches at a fixed frequency of 1.2MHz, allowing the use of tiny, low profile inductors and capacitors to minimize footprint and cost in space consideration applications for cellular phone backlighting or other hand held equipment.
The TS19370 is a step‑up DC/DC converter designed to drive white LEDs with a constant current. It can operate from a Li‑ion cell and drive 2‑9 LEDs in series, eliminating the need for ballast resistors. The device features a low 95 mV feedback voltage, 88 % typical efficiency, and an internal over‑output‑voltage protection that shuts down the driver when LEDs are disconnected.
The driver operates at a fixed 1.2 MHz switching frequency, allowing the use of tiny inductors and capacitors. Recommended external components include a 22 µH inductor, a 0.22 µF output capacitor, and a Schottky diode rated 100‑200 mA. Various dimming methods are supported, such as PWM on the SHDN pin or a filtered PWM signal that acts as an adjustable DC voltage.
| Input Voltage Range | 2.5 V – 18 V |
|---|---|
| Switching Frequency | 0.8 MHz – 1.6 MHz (typical 1.2 MHz) |
| Maximum Duty Cycle | 85 % – 90 % |
| Switch Current Limit | 320 mA |
| Over‑Voltage Protection (OVP) | 30 V |
| Feedback Reference Voltage | 95 mV |
| Typical Efficiency | 88 % (typical) |
| LED Drive Capability | Up to 9 LEDs (Vin 9‑15 V) |
It can drive up to nine white LEDs when powered from 9 V to 15 V.
The driver operates at a typical switching frequency of 1.2 MHz.
The internal OVP shuts down the device at 30 V.
A 22 µH inductor is recommended for most applications.