Smart Plug Reference Design – MP161 Non-Isolated Buck Regulator with ESP8266

Nowadays everything is connected. So why not also connect the wall plugs? Monolithic Power Systems presents a reference design with the MP161 part that will allow customers to join the IoT market. This is a two boards design, one for the dc-dc converter and the relay and the other for the Wi-Fi module. The configuration is designed to fit into a wall-plug.

This reference design is based on the MP161 which includes a 700V switching regulator, a low-dropout linear regulator and two channel relay drivers. The design includes Wi-Fi 802.11 b/g/n (HT20) protocol and 35.4mW active input power under stand-by operation.

The relay driver in the MP161 includes 2Ω on-state resistance, rail voltage up to 30V, integrated freewheeling diode, and a nominal off driver. The integrated LDO handles up to 30V input voltage; it delivers a fixed output of either 3.3V or 5V and includes over-temperature protection

Summary of MP161 Features

• Integrated 700V MOSFET and current source
• Constant voltage regulation with internal loop compensation
• Optimized light-load efficiency by frequency modulation
• Standby mode
• Anti-audible noise operation by peak current modulation
• Adjustable or fixed 12V Output
• Low operating current
• Integrated protection functions
  • Over-Temperature Protection (OTP)
  • Short-Circuit Protection (SCP)
  • Over-Load Protection (OLP)
  • Over-Voltage Protection (OVP)