With this device laser diodes can be driven by either the optical output power (using APC), the laser diode current (using ACC), or a full, controller-based power control unit. The maximum laser diode current per channel is 750 mA. Both channels can be switched in parallel for particularly high laser diode currents of up to 1.5A. A current limit can also be configured for each channel. Thanks to the high integration level of the analog functions for activation of the laser diodes with the microcontroller interface, multichannel laser diode control units can be implemented directly. Apart from the iC-HT only the microcontroller and laser diodes are required, the latter with varying wavelengths, for example. Internal operating points and voltages can be output through analog/digital converters.
The integrated temperature sensor permits the system temperature to be monitored and can also be used to check for feedback in the control circuit. Logarithmic digital/analog converters allow optimum power regulation across a large dynamic range enabling a variety of laser diodes to be used.
The relevant configuration is stored in two equivalent memory areas; internal current limits, a supply voltage monitor, channel-specific interrupt switching inputs, and a watchdog safeguard the operation of the laser diodes through iC-HT.
Alternatively, the device can be operated by pin configuration in place of the SPI or I2C interface, where external resistors define the APC performance targets. The iC-HT works on supply voltages of 2.8 V to 8 V and can thus drive both blue and green laser diodes. Operating temperatures range from -40 to +125°C. The device is housed in a 28-pin QFN package measuring 5x5mm.
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