ROHM Semiconductor BD18398A Current LED Drivers
ROHM Semiconductor BD18398A Current LED Drivers are 2-ch/3-ch synchronous buck DC-DC LED drivers using on-time topology. These drivers support a near-fixed switching frequency and fast regulation of the switching duty cycle. These devices use an average LED-current feedback buck topology to achieve more accurate LED-current regulation across a wide input-to-LED output range. The BD18398A supports individual 10-bit analog dimming and 10-bit PWM dimming for LED current by programming the 10-bit register via SPI. The ROHM Semiconductor BD18398A will enter LIMP-HOME mode if SPI communication fails. In the LIMPHOME mode, individual LED currents can be set via the external pins and maintained when input power is applied, without SPI communication.
Features
- AEC-Q100 qualified
- ISO 26262 process compliant to support ASIL-B
- On-time topology for near fixed frequency switching
- Average LED current regulation
- Protection diodes less for current sense pins
- Cycle-by-cycle switch overcurrent protection
- Thermal Shutdown (TSD)
- Thermal sensor reading
- Serial Peripheral Interface (SPI)
- LIMP-HOME mode
Applications
- Automotive exterior rear lamps
- Automotive turn
- Automotive DRL/position
- Automotive fog
- Automotive high/low beams
Specifications
- Continuous input voltage range
- VIN of 5V to 45V
- PIN of 5V to 65V
- 5VEXT of 4.5V to 5.5V
- 2.5V to 60V LED output voltage range
- 2.0A maximum output LED current/channel
- ±3% LED average current accuracy
- 5% to 100% 10-bit analog dimming range
- 200kHz to 2.25MHz programmable switching frequency range
- -40°C to +150°C junction temperature range
- 12.5mm x 8.1mm x 1.0mm [W (typ.) x D (typ.) x H (max.)] HTSSOP-C48 package
Typical Application Circuit
Block Diagram
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