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university:courses:electronics:buck_converter_basics [10 May 2019 19:55] – Update Arduino Sketch, use DownGit Mark Thoren | university:courses:electronics:buck_converter_basics [05 Feb 2024 20:30] (current) – "Promote" Slide Deck to top of page, formatting links Mark Thoren | ||
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* Open-loop vs. closed loop operation | * Open-loop vs. closed loop operation | ||
* Voltage-mode control | * Voltage-mode control | ||
+ | |||
+ | ===== Workshop Slide Deck ===== | ||
+ | A slide deck is provided as a companion to this exercise, and can be used to help in presenting this material in classroom, lab setting, or in hands-on workshops. | ||
+ | <WRAP round download> | ||
+ | **{{ : | ||
+ | </ | ||
===== Background: ===== | ===== Background: ===== | ||
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Solder-less breadboard and jumper wire kit or Perma Proto solder breadboard\\ | Solder-less breadboard and jumper wire kit or Perma Proto solder breadboard\\ | ||
ADALP2000 parts kit parts as required\\ | ADALP2000 parts kit parts as required\\ | ||
+ | Optional: **[[university: | ||
12V power supply (preferred) or 5V USB power supply (workable)\\ | 12V power supply (preferred) or 5V USB power supply (workable)\\ | ||
Voltmeter (optional, can use M2K in Voltmeter mode.)\\ | Voltmeter (optional, can use M2K in Voltmeter mode.)\\ | ||
- | LTspice files for this activity:\\ | + | LTspice files for this activity: |
- | {{ : | + | |
===== Activity 1: An Open-Loop 2:1 Buck Converter ===== | ===== Activity 1: An Open-Loop 2:1 Buck Converter ===== | ||
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==== Circuit Construction and Testing ==== | ==== Circuit Construction and Testing ==== | ||
Build the following breadboard circuit for the buck converter, following the schematic in Figure 16. (Q1, R2, R3 can be added later.) Note that the HPH1-1400L has six inductors that can be connected in any way (series, parallel, or a combination of the two). Be sure to observe proper polarity, connecting all inductors in series as shown. | Build the following breadboard circuit for the buck converter, following the schematic in Figure 16. (Q1, R2, R3 can be added later.) Note that the HPH1-1400L has six inductors that can be connected in any way (series, parallel, or a combination of the two). Be sure to observe proper polarity, connecting all inductors in series as shown. | ||
+ | <WRAP info> | ||
+ | The circuits in this lab are compatible with solderless breadboard construction. However they are relatively complicated and take time to construct and debug. The [[university: | ||
+ | </ | ||
{{ : | {{ : | ||
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Copy this Arduino sketch into your Arduino sketchbook (and restart the Arduino IDE if it's open.) | Copy this Arduino sketch into your Arduino sketchbook (and restart the Arduino IDE if it's open.) | ||
- | + | <WRAP round download> | |
- | * Arduino Sketch: [[ https:// | + | * Arduino Sketch: |
+ | </ | ||
The following figure shows the operation of the closed-loop circuit. The setpoint voltage is 3.141V, and the purple trace starts out close to this value at the lefthand side of the Scopyshot. A 50 ohm load is then connected to the output, drawing approximately 120mA, and producing a dip in the output voltage. The Arduino loop detects this and increases the PWM frequency accordingly, | The following figure shows the operation of the closed-loop circuit. The setpoint voltage is 3.141V, and the purple trace starts out close to this value at the lefthand side of the Scopyshot. A 50 ohm load is then connected to the output, drawing approximately 120mA, and producing a dip in the output voltage. The Arduino loop detects this and increases the PWM frequency accordingly, | ||
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<WRAP round download> | <WRAP round download> | ||
**Resources: | **Resources: | ||
- | * LTSpice files: [[ https:// | + | * LTSpice files: |
- | * Fritzing files: [[ https:// | + | * Fritzing files: |
- | * JavaScript files: [[ https:// | + | * JavaScript files: |
</ | </ | ||
===== Going Further ===== | ===== Going Further ===== | ||
- | This activity borrows heavily from Analog Devices Application Note 140, which is an excellent reference to build upon concepts in this activity: | + | This activity borrows heavily from Analog Devices Application Note 140, which is an excellent reference to build upon concepts in this activity:\\ |
+ | **[[http:// | ||
- | http:// | + | AN19 is the LT1070 design manual, rich with examples: |
+ | **[[http:// | ||
- | AN19 is the LT1070 design manual, rich with examples: | + | Article on simulating SMPS loop gain (and why it's often unnecessary): |
- | http:// | + | **[[http:// |
- | + | ||
- | Article on simulating SMPS loop gain (and why it's often unnecessary): | + | |
- | http:// | + | |
===== Questions: ===== | ===== Questions: ===== | ||
- | **Return to Lab Activity | + | Return to **[[university: |
+ | Return to **[[university: |