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university:courses:electronics:electronics-lab-32 [25 Jan 2019 13:44] – add ltspice files Antoniu Miclausuniversity:courses:electronics:electronics-lab-32 [23 Aug 2019 14:02] – Antoniu Miclaus
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 =====Hardware Setup:===== =====Hardware Setup:=====
  
-AWG1 is connected as V<sub>IN</sub> and should be configured as a sine wave with an amplitude greater than 6 volts, zero offset and a frequency of 100 Hz. The scope inputs are used to monitor various points around the circuit such as V<sub>IN</sub>, V<sub>OUT</sub>, the voltage across R<sub>S</sub> and thus the current through R<sub>S</sub>, and the gate of M<sub>1</sub>.+AWG1 is connected as V<sub>IN</sub> and should be configured as a sine wave with an amplitude greater than 6 volts peak-to-peak, zero offset and a frequency of 100 Hz. The scope inputs are used to monitor various points around the circuit such as V<sub>IN</sub>, V<sub>OUT</sub>, the voltage across R<sub>S</sub> and thus the current through R<sub>S</sub>, and the gate of M<sub>1</sub>.
  
 {{ :university:courses:electronics:active_rectifiers_hardware_setup.png |}} {{ :university:courses:electronics:active_rectifiers_hardware_setup.png |}}
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 =====Questions:===== =====Questions:=====
  
-Change the peak amplitude of the AC input waveform. What is the minimum peak value of the AC input where the PMOS transistor is still actively rectifying the input, i.e. the V<sub>GS</sub> is greater than the threshold voltage and the device is turned on? What determines this minimum voltage?+Change the peak-to-peak amplitude of the AC input waveform. What is the minimum peak value of the AC input where the PMOS transistor is still actively rectifying the input, i.e. the V<sub>GS</sub> is greater than the threshold voltage and the device is turned on? What determines this minimum voltage?
  
 Try different frequencies for the AC input. How does the frequency effect the peak value and the width  of the current pulse in R<sub>S</sub>? Try different frequencies for the AC input. How does the frequency effect the peak value and the width  of the current pulse in R<sub>S</sub>?
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 There are other potential uses for a circuit that essentially allows current flow in only one direction with very low voltage drop across the switch. In battery chargers, where the input power source might be intermittent such as a solar panel or wind turbine generator, it is necessary to prevent the battery from discharging when the input power source is not generating a high enough voltage to charge the battery. Generally a simple Schottky diode is used for this purpose but as was pointed out in the background section this can lead to losses in efficiency. If an op amp with sufficiently low operating supply current is employed this can often be lower than the reverse leakage current in a large Schottky diode. There are other potential uses for a circuit that essentially allows current flow in only one direction with very low voltage drop across the switch. In battery chargers, where the input power source might be intermittent such as a solar panel or wind turbine generator, it is necessary to prevent the battery from discharging when the input power source is not generating a high enough voltage to charge the battery. Generally a simple Schottky diode is used for this purpose but as was pointed out in the background section this can lead to losses in efficiency. If an op amp with sufficiently low operating supply current is employed this can often be lower than the reverse leakage current in a large Schottky diode.
  
 +<WRAP round download>
 **Resources:** **Resources:**
   * Fritzing files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/fritzing/active_rectifier_bb | active_rectifier_bb]]   * Fritzing files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/fritzing/active_rectifier_bb | active_rectifier_bb]]
   * LTspice files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/ltspice/active_rectifier_ltspice | active_rectifier_ltspice ]]   * LTspice files: [[ https://minhaskamal.github.io/DownGit/#/home?url=https://github.com/analogdevicesinc/education_tools/tree/master/m2k/ltspice/active_rectifier_ltspice | active_rectifier_ltspice ]]
 +</WRAP>
  
 **For Further Reading:** **For Further Reading:**
university/courses/electronics/electronics-lab-32.txt · Last modified: 25 Jun 2020 22:07 by 127.0.0.1

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