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Power Bank | Cypress Semiconductor

Block Diagram

Cypress's PSoC® 1 family incorporates Programmable System-on-Chip (PSoC) technology to implement an integrated single-chip power bank solution. PSoC 1 eliminates the external battery charging and battery protection circuits. It controls charging of battery and the load by controlling Buck and Boost converters through PWMs. The PSoC measures the battery current and adjusts the pulse width of the Buck PWM using a P-I loop to accurately control the charging current. It charges the battery using constant current mode and when the battery voltage reaches full charge, it changes over to constant voltage charge and terminates the charge when the battery current goes below a predefined value. The PSoC also monitors the load current and disables the boost PWM either on overload or when the load is disconnected. It implements battery temperature measurement and cuts off charging or discharging when the temp is above or below specified thresholds. Also, it drives status LEDs through GPIOs to indicate battery charging or discharging status.

Design Considerations

Power bank is a device that stores power in a Li-Ion battery. It is being increasingly used as reserve charger for hand held/portable devices like mobile phones, tablets etc. A typical power bank has these components:

Charging circuit: it implements the complete charging logic for a Lithium Ion battery

Battery Protection circuit: it takes care of over charge and over temperature protections during charging and over discharge, over load and temperature protections during discharge.

Boost Converter: it steps up the 3V - 4.2V battery voltage to 5V.

Controller functions:

  • Monitors output voltage and controls the pulse-width of gate drive of the MOSFET in boost converter.
  • Measures battery voltage and disables boost converter when battery voltage reaches the low voltage threshold.
  • Monitors the load current, turns off the boost converter when load is disconnected or when there is an overload.
  • Drives status LEDs to display battery level and charging or load status.

PSoC 1 provides a single-chip solution that integrates battery charging, battery protection and controller functions in a single chip; thus reducing BOM and PCB size. If required, an external hardware battery protection circuit can also be added for additional battery protection.

Reference Designs


PSoC 1 is the world's first Programmable embedded System-on-Chip integrating configurable analog and digital peripheral functions, memory, and a microcontroller on a single chip. Powered by Cypress's proprietary 8-bit M8C core, the PSoC 1 portfolio of devices provides the system designer analog integration, flexible IO routing and complete control of power consumption. Following products from our PSoC 1 CapSense Plus portfolio are best fit for power bank applications.


Explore other product from PSoC 1 portfolio based on your applications needs.

PSoC 1 Portfolio

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Technical Articles
This article discusses how to implement a li-ion battery charger by using CC-CV battery charging profile.
This article discusses the various errors involved in an analog signal chain and how to calibrate them for precise measurement using flexible architecture of PSoC 1.

Software and Drivers

  • PSoC Creator

    PSoC Creator is a state-of-the-art software development IDE combined with a revolutionary graphical design editor to form a uniquely powerful hardware/software co-design environment.

  • PSoC Designer

    PSoC Designer is the revolutionary Integrated Design Environment (IDE) that you can use to customize PSoC to meet your specific application requirements. PSoC Designer software accelerates system bring-up and time-to-market.