Questions tagged [pmos]

A p-channel metal-oxide semiconductor (pMOS) transistor which has has p-type carriers used in the channel. The channel is established by a negative voltage on the gate which inverts the substrate (NWell) under the gate which turns the device on. The term may also be used to describe logic circuits built around pMOS transistors.

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PMOS Load Switch Circuit issue

I'm working on a load switch circuit that drives a capacitive load of 1000 uF and a GaN transistor in parallel. The schematic of the circuit is attached. The input voltage is 50 V and the ...
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40 views

PMOS Drain-Source Short at Turn-On

In the attached image, without C1 & C2 (used only as de-cap) mounted, when 24V is given at TP1 and nMOS (Q1) is turned ON, the circuit works fine and I get 24 V at TP3. But when C1 & C2 are ...
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466 views

What is the best between a transistor and a pmos and which resistances

I need to create a switch to power on or off a moisture sensor. PIN 10 is HIGH or LOW to trigger either the transistor or the PMOS My sensor consume about 0.6mA Moisture sensor information My ...
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123 views

Problem with charge transfer equation

I'm confused on the two equations(refer to the figure: enclosed in red square) This is a 4-stage pmos charge pump, I understand why its delta Qg is multiplied by 4(underlined red) same goes with the ...
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49 views

555 timed power at high to low edge in battery powered circuit

I have a lovely Atmel touch sensor whose output is high only as long as it's touched. I want both off-on and on-off edges of its output to initiate two 3 sec pulses (and the time between edges is > 3 ...
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42 views

Parking Light And Signal light with same LED using MOSFETS

I have a project where I have an existing 12v parking light and I want to also have the turn signal use the same light. I've constructed a circuit using 2x NMOS and 1x PMOS. I think it will work and ...
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46 views

Back-to-Back PMOS high power dissipation

I have created a circuit in LTspice to switch between two power sources (10s Li-Ion batteries). V1 and V3 resemble the power sources which vary from 30-42V. V2 and V3 are output pins of an µC. R3 is ...
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35 views

Deriving PU / PD given a sketch of a PMOS

For the PMOS given below I can derive the function f, such that f inverted in its variables corresponds to the expression of PMOS(f) and f inverted equals NMOS(f). For this specific problem I have ...
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108 views

Multiplexed LED column driver MOSFET doesn't fully turn off without a resistor parallel to the LEDS

I have a board with a 16x10 led matrix. The columns are switched with DMG9933 Dual P mosfets. The rows are driven with a constant current led driver ST STP16CPC26 (similar to TI TLC5956) I noticed ...
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30 views

Understanding PMOS's and NMOS's

The problem says solve assuming VI = 0, +2.5V, and -2.5V. I know that if VI = -2.5V the MOSFET's are in cutoff and that VDS = 0. and IDP and IDN will = 0, but would V0 also = 0? If VI = 0 the ...
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26 views

Output voltage for pmos with Vt= -0.8

simulate this circuit – Schematic created using CircuitLab What is VX? I am having confusion between 2.8 V or 3 V. Thank you for your help.
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21 views

Mixing Reverse Polarity Protection PMOS with a Piezo Element

I have a circuit that powers some leds when vibrations are detected. I am trying to integrate a PMOS for reverse polarity battery protection. When the PMOS is present the circuit simulation fails as ...
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86 views

Design Vbat system with PMOS to keep RTC

Since I'm using an MCU without internal Vbat system (STM32L0 series), I've read the "How to design a Vbat on STM32L0/L1 series" from STMicroelectronics to keep the internal RTC. I would like to ...
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44 views

CMOS Inverter output for a given transfer characteristics

I have tried solving the below CMOS problem with a given transfer characteristics but my answer is wrong. Answer should be 0.25. Could someone please point out where I went wrong ?
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177 views

LTSPICE Model Parameters of P-MOSFET

I am trying to simulate a circuit including TSM500P02CX P-MOSFET. The manufacturer of the MOSFET doesn't provide SPICE Model, so ...
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62 views

Inversion Region

If one transistor in a circuit (say common source with active load) operate at the strong inversion region, should the rest of the transistor also operate on that same region? Or will it depend?
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44 views

What would happen if there is no ground in a PMOS inverter?

I understand why when there is a ground you need a resistor or an NMOS but what if there were no ground at all and simply A goes high, B is 0, A goes low, current flows from VDD to B through the p ...
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252 views

Driving a 35V PMOS circuit from a Grounded/Floating input

I have an application where I need to switch a contactor on and off using a spare output of an off the shelf Battery Management System (BMS) The input is the signal coming from the BMS, while the ...
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35 views

Deriving the Transistor Width for NOR

I'm an undergraduate electrical engineer and my universities notes are not the best, I have an assignment in which I do not want the answers to but the question has given me the oxide capacitance, ...
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442 views

Why not switching extra inverters with opposite MOSFETs in CMOS XOR gate?

Below you can see a CMOS XOR gate. I wonder why we do not change extra inverters like A' or B' with opposite MOSFETs. For example, could not we just put the green construction in the place of red ...
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105 views

Soft latch on/off button simulation

I am trying to simulated in pspice a soft latch on/off circuit but it is not working as expected, even if I double check the implementation. Can someone explain to me why the voltage on the probe is 0....
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44 views

Looking for the logical equation from this PMOS circuit

I am looking for the logical equation that describes the given circuit below. Unfortunately I don't have information whether \$U_b\$ is positive or negative - would that make a difference? I derived ...
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112 views

Dual Power Management with MOS

I am working on a design with 2 12V power supply, one external and one from a battery. The current needed is about 7-8A. I could have use schottky or simple diode to protect one supply from another ...
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149 views

PMOS reverse polarized - 12v light

I've this circuit: simulate this circuit – Schematic created using CircuitLab I have a doubt, when I press the SW1 the LAMP1 turns on, when I press the SW2 the light turns on but the P channel ...
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456 views

How to prevent high side PMOS from glitching?

I want to use a PMOS-Transistor as a high side switch like so: simulate this circuit – Schematic created using CircuitLab But when I tested this circuit on a breadboard, there was always a ...
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241 views

Extrapolating Transistor DC Current Gain Graphs?

I'm working on a design which will use a BJT to switch 2 PMOS gates low to power 2 separate loads. I am going to drive the transistor from a NOR gate. From my transistors datasheet, I thought I could ...
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327 views

Reverse Current Protection using two PMOS in back to back configuration

I am working on a circuit that needs reverse current protection. Back to back mosfet configuration has been suggested by many people, and it seems to make sense at the beginning. But after I built my ...
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550 views

PMOS soft turn on slower current ramp up to capacitive load

I'm trying to understand MOSFET soft switch and I know the more common off-the-shelf configuration is to put the capacitor between gate and Vo. However, I'm trying to understand why I can't do it in ...
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348 views

Using LTSpice to find the gain of NPN-PMOS folded cascode

I am trying to use LTSpice to find the gain of NPN-PMOS folded cascode. Below is the question prompt: In the problem, the parameter specifications are as follows: \begin{equation} \beta =100,\:V_A=5V\...
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1k views

Channel doping change to control the threshold voltage in an NMOS

By increasing the P-doping in an NMOS, threshold voltage is increased. How does it happen? And why? And what elements do they use for this? can anyone give me a reference or explain?