LED control chips enable more efficient automotive lighting designs
Capable of driving two strings of LEDs up to 60 V, the NCV78763 provides an efficient single-chip automotive lighting solution. Each output supports a DC current of 1.6 A. An integrated current-mode voltage booster controller enables input current filtering. Dimming is also supported via pulse-width modulation of the supply current at frequencies up to 4 kHz. In addition, the device also can feed the PWM signal directly from the external microcontroller.
Optimized for front lighting applications, the NCV78763 can be employed in high beam, low beam, turn indicator, static cornering, fog and daytime running lights. Each individual LED channel is equipped with an independent buck switch output, through which both the output current and voltage can be set to meet specific application criteria. Configuration is done via the device’s serial peripheral interface (SPI).
Integrated diagnostic features offload the system microcontroller, which improves the overall effectiveness of the lighting design. If more than two LED channels are required on one lighting module, then multiple NCV78763 devices can be combined together. Due to the serial peripheral interface (SPI) programmability, this solution is highly flexible – permitting the scaling up of designs so that more LED strings can be utilized. This results in multiple system configurations, which are able to address an expansive range of automobile models, with significantly faster design cycles and lower engineering overheads. The NCV78763 supports high operating frequencies and thus permits specification of smaller inductors which in turn translates into lower bill of materials costs.
Also being introduced at Electronica is the NCV7691 current controller. Targeted predominantly at automotive rear combination lamps (RCL), centre high-mounted stop lamps (CHMSL), and day-time running lights (DRL), this highly integrated pre-driver contains PWM and diagnostic capabilities, as well as battery connection and negative temperature coefficient (NTC) input in a single chip. Through external bipolar transistor(s) combined with feedback resistors, the chip is capable of regulating the LED driver current with up to eight LED strings being driven concurrently. It gives lighting designers the flexibility to add channels to create multi-channel systems.
A dedicated dimming feature is included via the PWM input pin. LED brightness levels can be programmed in a straightforward manner using external resistors in series with the bipolar transistor. This approach gives engineers the ability to use this device over a wide range of currents. Set back power limit reduces the drive current during over-voltage conditions. Open LED string and short-circuit diagnostic functions ensure that operational reliability is maintained. By connecting the FLTS pins together, multiple devices can be turned off in case of a detected error. AEC-Q100 qualified, the NCV7691 can deal with harsh automotive environments and operating temperatures ranging from -55 °C to +150 °C .
More information:
https://www.onsemi.com/PowerSolutions/product.do?id=NCV78763
https://www.onsemi.com/PowerSolutions/product.do?id=NCV78763
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