AFE4490 Driving OLEDs at 9V

Hello Yasser,

LED_DRV_SUP and TX_CTRL_SUP are recommended to be tied together to the same supply (between 3.0 V to 5.25 V). Hence higher voltages (greater than 5.25V) is not supported for H-bridge configuration.

In Common Anode configuration, the external supply (connected to the common anode of the two LEDs) must be high enough to account for the forward drop of the LEDs as well as the voltage headroom required by the current source and switches inside the AFE. In most cases, this voltage is expected to fall below 5.25 V; thus the external supply can be the same as LED_DRV_SUP. However, in certain cases (for instance when two LEDs are connected in series or driving the LEDs at higher voltages) where the voltage required on the external supply is higher than 5.25 V. Such a case must be handled with care to ensure that the voltage on the TXP and TXN pins remains less than 5.25 V and never exceeds the supply voltage of LED_DRV_SUP, TX_CTRL_SUP by more than 0.3 V.

Hi Praveen, 

Thanks for the prompt reply. Let say I've connected the OLEDs in push-pull mode (9 V drive) and the voltages at TXP and TXN are less than 1 V. What should be the TX_CTRL_SUP? How does the H-Bridge Driver work? 

Thanks, 
Yasser