The A6210 from Allegro MicroSystems Europe is an LED driver IC based on a buck (stepdown) regulator circuit using constant ‘on’ time with valley current-mode control.
This control scheme allows the use of very short switch ‘on’ times, making the new device ideal for applications requiring high switching frequencies combined with high input voltages and low output voltages. The small size and high efficiency of the A6210 makes it suitable for applications where space is limited - inside small MR16 lamps, for example - while its high current and medium-voltage capability mean that it can also be used in high-power applications such as street lighting. System cost is reduced as a result of the high switching frequencies (up to 2.0 MHz), which allow small, low-value ancillary components such as inductors and capacitors to be used. In addition, fewer external components are required because of the high levels of integration in the device, which includes a 3-amp switch. Optimal drive circuits are used to minimise switching losses, allowing over 90% efficiency in realistic conditions. The switching frequency is maintained constant, as the input voltage modulates the ‘on’ time. This feed-forward control ensures excellent line correction. An external resistor pulled up to the input supply programs the ‘on’ time. The A6210 will operate over a wide input voltage range of 9 to 46 V, including 12 V nominal or maximum Class II power supplies, and produces an output voltage over the range from 0.8 to 40 V. This means that it can drive a single LED or a series string of ten or more LEDs. The output current rating of 3 A, combined with the internal switch, allow it to directly drive the new generation of very high current LEDs and LED modules. Standby current is less than 100 µA. The A6210 is supplied in a 4-mm QFN package.