ZHCSCO5B June 2014 – February 2018 DLPA2000
PRODUCTION DATA.
The LED drive current is controlled by a current digital-to-analog converter (DAC) and can be set independently for switch SW4, SW5, and SW6. The DAC is trimmed at a current of 750 mA for the DLPA2000 at code: 0x307h. The DLPA2000 current step size is 0.95 mA.
First order gain-error of the DAC can be neglected, but an offset current error must be taken into account. This offset error differs depending on the used RLIM and will be ±25 mA for the DLPA2000 for a 100-mΩ current sense resistor.
The max current of the DLPA2000 (SWx_IDAC[9:0] = 0x307h) is regulated to 750 mA. At the lowest setting (SWx_IDAC[9:0] = 0x001h) the current is regulated to 14 mA for the DLPA2000. For this current setting (0x001h), the absolute current error results into a large relative error; however, this is not a typical operating point.
Be aware that the LED current setting not only depends on the accuracy of the RLIM resistor, but also strongly depends on the added resistance of PCB traces and soldering quality. Due to the low value of the current sense resistor RLIM, any extra introduced resistance (for example several mΩ) will result in a noticeable different LED current.