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PSoC 5, 3 & 1 MCU

PrateekKumar
New Contributor II

Hi,

I have been working to implement a circuit on PSoC5LP MCU as the PSoC5 LP MCU supports both analog and digital peripherals but in analog we have 4 comparators and 4op-amps, what in the situation if we require MOSFET in the situation, then what should be my approach? 

Anyone Please do let me know, waiting for your reply.

Thanks & Regards,

Prateek

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1 Solution
Len_CONSULTRON
Honored Contributor II

Prateek,

The PSoC5 is a CMOS part.   This means that virtually all digital switching that occurs internally to the part are ultra low-power FETs.  The FETs being used to drive GPIO are low-power (without the 'ultra').

The PSoC IC's maximum power dissipation is most likely about 300mW.  (It's not listed in the Family datasheet.)   This is because it does not provide low Rds in the FETs and has no heat pad/slug on the bottom of any of the parts.    

In summary the PSoC5 is a signal-level part.   It is not power-rated.  For this part, the lower the total power dissipation required will improve all the functions of the part especially the analog functions such as ADCs and DACs.

Len
"Engineering is an Art. The Art of Compromise."

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13 Replies
Len_CONSULTRON
Honored Contributor II

Prateek,

Can you be more specific about the MOSFET reference?

Do you have a specific MOSFET part to which you want to create an interface?

Many MOSFETs used as switches can be controlled using digital signals.   If the MOSFET is to act as a analog component, you can use PSoC analog resources.

Len
"Engineering is an Art. The Art of Compromise."
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PrateekKumar
New Contributor II

Hi Len,

So the analog resources contain MOSFET too, as in datasheet it contains only comparators and        op-amps, please do let me know

 

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Len_CONSULTRON
Honored Contributor II

Prateek,

The PSoC5 is a CMOS part.   This means that virtually all digital switching that occurs internally to the part are ultra low-power FETs.  The FETs being used to drive GPIO are low-power (without the 'ultra').

The PSoC IC's maximum power dissipation is most likely about 300mW.  (It's not listed in the Family datasheet.)   This is because it does not provide low Rds in the FETs and has no heat pad/slug on the bottom of any of the parts.    

In summary the PSoC5 is a signal-level part.   It is not power-rated.  For this part, the lower the total power dissipation required will improve all the functions of the part especially the analog functions such as ADCs and DACs.

Len
"Engineering is an Art. The Art of Compromise."

View solution in original post

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PrateekKumar
New Contributor II

Hi Len_CONSULTRON

So a quick doubt how much Rds is being provided by PSOC5LP.

 

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PrateekKumar
New Contributor II

A small doubt too that can we implement TPS25982 on PSOC5 LP, I will be providing the link:

https://www.ti.com/lit/gpn/tps25982

Page:18 Functional Block Diagram I just need to implement, what will be your idea could you please share it.

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WaMa_286156
Contributor II

I do not know what you are trying to do with this part.  You don't need more than resistors to control and use that part.  Unless you want the PSOC to monitor its "power Good" reading.  In that case, the Rpg (100K) on the FIRST page is connected to the PSOC power supply (3.3v or 5v) and the PG output goes into the input pin on the PSOC.  You can then use the PSOC to send a message or trigger an alarm.  Easy.

 

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WaMa_286156
Contributor II

I am also curious about what you mean.   However, assuming you are talking about N Channel FET's being driven by the PSOC 5LP, I do that all the time.

The property to pay attention to on a MOSFET is the Gate Threshold Voltage when being controlled by a PSOC 5LP.

If you want the FET to turn on hard, the Gate Threshold Voltage must be less than the maximum voltage available at the I/O pins, which depends upon your power supply, and in the PSOC 5 is 5 volts maximum.  There is always a range of values for the GTV.

Note that if you use a "typical" GTV of 3 volts, some parts will fail to operate because a 3 volt typical may have a 6 volt maximum as an allowable range for a "good" part.

When driving the gate of the FET, used Strong Drive, Direct (not resistive pullup or pulldown).  If you use Pull up or pull down, your FET will turn on or off fairly slowly, and that can cause problems.  You may wish to put a 10 ohm resistor in series with the FET Gate to avoid peak current problems due to gate capacitance.

 

 

 

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PrateekKumar
New Contributor II

Hi WaMa_286156

A simple question how you gonna control MOSFET using PSOC5LP as only analog resources available is comparators and Op-Amps, that's what I am asking

 

 

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WaMa_286156
Contributor II

at this blog post:  https://socmaker.com/?p=442   You will see how I connected a digital output to a Darlington Transistor.  To use an FET, the Gate is connected to from the output pin rather than the Base of the Darlington.

Connected to Darlington (could be an FET)Connected to Darlington (could be an FET)

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odissey1
Honored Contributor II

WaMa,

I believe that PrateekKumar wants to control the high-side FET as shown on TPS25982 power supervisor schematic, which is rated up to +24V. This FET needs either external high-side driver or another FET to decouple from 24V input. It looks more like a didactic exercise at this point. 

odissey1_0-1611606858401.png

 

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WaMa_286156
Contributor II

WaMa_286156_0-1611610651799.png

  Yes, that is why I indicated he only needed resistors to control the device, but the pg output can be connected to the PSOC.   I think what you are getting at is he has no EE around him to help with the N/P channel FET pair for interfacing to the Enable.    Also no 5V power supply from the Voltage In, etc.  

Agreed.  Lost cause.

 

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PrateekKumar
New Contributor II

Which PSoC version do you think will be best for implementing the TPS25982? Is it PSoC5LP or PSoC6

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WaMa_286156
Contributor II

It depends upon what you want to do with it.  If you are *only* monitoring the Power Good signal (PG), and you do NOT need to send that information wirelessly, then the PSOC 5 with PSOC Creator is easier to understand and work with.  It typically draws 30 milliamps at 5 volts when running at about 20 mhz.

If you are needing to use BlueTooth, then PSOC 4 Bluetooth family, or PSOC 6 BLE would probably be a better choice.  The CY8Ckit-059 is a $10 to $15 test board for PSOC 5 (see socmaker.com), and the CY8CPROTO-063-BLE is a $20 blue tooth test board for PSOC 6.

The PSOC 63 is a true PSoC, with UDB's.  There are fewer in that one than in the PSOC 5, which means complex digital designs would be more difficult, but your job appears (on the surface) to be easy.

If this is for college, I would get a clarification from Teachers Aides on what the goal of the project is.  If for work, same thing from your supervisor.  That will determine what you need to do next.

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