In order to reduce chip count in high volume applications, consider integrating a power supply controller. In my case I need a hot ground power supply. The common chip for doing this is a Power Integrations LNK302 or LNK304. Datasheet: http://ac-dc.power.com/design-support/p ... ata-sheet/
The LN302 integrates the needed FET, but with the ESP-type chips you might want to use an external FET to provide more flexibility. Change the FET to increase the current output.
An ideal integrated power supply controller would be flexible to do all of this....
1) Hot ground constant voltage supply - use case: dimmers, outlets
2) Hot ground constant current supply - use case: LED bulbs
3) Buck-boost supply - batteries
Once the power supply controller is integrated it becomes possible to add some extreme 'Green' features to the chip. For example - when the chip is ready to use wifi it could instruct the power supply controller to fully charge up the output capacitor. When in deep sleep it could be smart enough to only charge the output cap once every 50 cycles. This helps solve one of the main problems with smart LED light bulbs - they draw too much power when they are off. Under IEC62301 if standby power is 5mW of less, you can advertise it as Zero power consumption in the EU. This may be achievable with an integrated power supply controller.