Understanding the power PCB design

P

Phoenix

New member
Hi all,

I'm trying to better understanding of design decisions regarding the power PCB eg
( https://github.com/Starsurfer78/TeensyMower-PCBs/blob/main/Power_PCB_v109/charge_pcb.pdf )

is there any chance that someone could tell me what purpose the following components serve

Capacitor C1,
Schottky diode D4
Schottky diode D5
Schottky diodes D6-10

Also is there a reason that d4 is different to the other schottkey diodes?

Are any of these components meant to be for flyback protection, reverse polarity, motors acting as dynamos when manually turned, etc?
 
D3 and D5 are the same. They are designed to limit the flow of current in the right direction.
D1 and D4 I took it from a switching example and they are also intended as simple protection.
D6 -D10 has been added by Bernard
 
The two components that I'm most curious about is D4 and C1.

I'm not an Electrical Engineer so any assumptions of mine are probably wrong. However, my initial assumptions were that D5 serves as reverse polarity protection from the battery source.

It looks like D6-10 also are to protect against reverse polarity - I'd assume the concern is that if a motor was turned manually that it would act as a dynamo and generate electricity - which might cause reverse polarity issues.

As for C1 my guess is that the polarized capacitor combined with D6-10 might act as a filter to smooth out voltage spikes due to the inductive nature of dc motors - capacitors are often bridged across the terminals of brushed DC motors for this reason (Also see the first video below) - that might also explain why there isn't a C2 on the charging side of the circuit? Another possibility is that the capacitor might be some kind of flyback protection for Back EMF - I've seen a few designs online where a Schottky diode is connected in the reverse polarity across the motor terminals or other inductive loads to dissipate that energy ( see https://www.gammon.com.au/motors ).


 
The Switch is similar to this, but with other Components:
www.circuits-diy.com

Arduino High Voltage Driver Circuit Using IRF9540 Power MOSFET

Control current/voltage requirements are often higher than what can be handled directly. Today, we will build an Arduino high voltage driver
www.circuits-diy.com www.circuits-diy.com

Yes C1 is intended as a small filter/spike to smooth the voltage.

The Schottky diodes are intended to prevent one type of dynamo.

But my knowledge of electronics is also very limited and I relied on Samples on the internet.
 
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