User Manual

P A G E 8

E a s y P I C v 8 M a n u a l

P O W E R S U P P L Y

P A G E 8

Power supply unit

The power supply unit (PSU) (1) provides clean and regulated power, necessary for

proper operation of the development board. The host MCU, along with the rest of the

peripherals, demands regulated and noise-free power supply. Therefore, the PSU

is carefully designed to regulate, ﬁ lter, and distribute the power to all parts of the

development board. It is equipped with three diﬀ erent power supply inputs, oﬀ ering

all the ﬂ exibility that EasyPIC v8 needs, especially when used on the ﬁ eld. In the case

when multiple power sources are used, an automatic power switching circuit with

predeﬁ ned priorities ensures that the most appropriate will be used.

The PSU also contains a reliable and safe battery charging circuit, which allows a

single-cell Li-Po/Li-Ion battery to be charged. Power OR-ing option is also supported,

providing uninterrupted power supply (UPS) functionality when an external or USB

power source is used in combination with the battery.

Detailed description

The PSU has a very demanding task of providing power for the host MCU and all the

peripherals onboard, as well as for the externally connected peripherals. One of the key

requirements is to provide enough current, avoiding the voltage drop at the output.

Also, the PSU must be able to support multiple power sources with diﬀ erent nominal

voltages, allowing switching between them by priority. The PSU design, based on a

set of high-performance integrated devices produced by Microchip, ensures a very

good quality of the output voltage, high current rating, and reduced electromagnetic

radiation.

At the input stage of the PSU, the MIC2253, a high-eﬃ ciency boost regulator IC

with overvoltage protection ensures that the voltage input at the next stage is well-

regulated and stable. It is used to boost the voltage of low-voltage power sources

(a Li-Po/Li-Ion battery and USB), allowing the next stage to deliver well-regulated

3.3V and 5V to the development board. A set of discrete components are used to

determine if the input power source requires a voltage boost. When multiple power

sources are connected at once, this circuitry is also used to determine the input

priority level: externally connected 12V PSU (2), power over USB (3), and the Li-Po/Li-

Ion battery (4). The transition between available power sources is seamless, providing

uninterrupted operation of the development board.

E a s y P I C v 8 M a n u a l

(1) This image is only for demonstration purpose, please do not

remove the PSU plastic cover nor touch any of the components

below. The development board can be permanently damaged.

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