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--- modular_synthesizers:negative_buck [2024/06/17 21:24] – [What do commercial modules consume and how are they built?] utedass
+++ modular_synthesizers:negative_buck [2024/06/22 10:08] (current) – [Implementing a negative buck regulator] utedass
@@ Line 48: / Line 48: @@
 ^ Model ^ Brand ^ +12V mA ^ -12V mA ^ +5V mA ^ Technique ^ Comments ^ Links ^
-| Castor and Pollux II | Winterbloom | 100 | 35 | - | LDO 3.3V | Could benefit ALOT with buck | [[https://winterbloom.com/shop/castor-and-pollux|Info and shop]] [[https://github.com/wntrblm/Castor_and_Pollux/blob/main/hardware/mainboard/mainboard.pdf|Schematics]] |
+| Castor and Pollux II | Winterbloom | 100 | 35 | - | LDO 3.3V | Could benefit alot with buck | [[https://winterbloom.com/shop/castor-and-pollux|Info and shop]] [[https://github.com/wntrblm/Castor_and_Pollux/blob/main/hardware/mainboard/mainboard.pdf|Schematics]] |
 | Blinds | Mutable Instruments | 70 | 70 | - | 24V fed ICs | Could benefit alot with buck | [[https://pichenettes.github.io/mutable-instruments-documentation/modules/blinds/|Info]] [[https://pichenettes.github.io/mutable-instruments-documentation/modules/blinds/downloads/blinds_v60.pdf|Schematics]] |
 | DIY Modulator | Erica Synths | 27 | 22 | - | 24V fed ICs |  | [[https://github.com/erica-synths/diy-eurorack/blob/master/Modulator%20DIY.zip|Schematics]] |
 | VCF-4 | Skulls & Circuits | 163 | 91 | - | Mostly 24 fed ICs, some 12V and some LDO 5V fed | Could probably benefit alot from switch mode regulators | [[https://www.skullandcircuits.com/vcf-4/|info]] [[https://www.skullandcircuits.com/wp-content/uploads/2023/04/VCF-4-v5.2.pdf|Schematics]] |
+| BURST | Befaco | 56 | 10 | - | LDO 5V and probably some 24V fed ICs |  | [[https://www.befaco.org/burst-2/|Info]] [[https://befaco.org/docs/Burst/Burst_V3_Schematic.pdf|Schematics]] |
 |  |  |  |  |  |  |  |  |
+|  |  |  |  |  |  |  |  |
+===== Other work on the topic =====
+[[https://www.analog.com/en/resources/technical-articles/positive-buck-regulator-makes-negative-boost-dcdc-converter.html|Positive Buck Regulator Makes Negative Boost DC/DC Converter]]
+[[https://www.ti.com/lit/an/slyt516/slyt516.pdf?ts=1717195408219&ref_url=https%253A%252F%252Fwww.google.com%252F|Designing a negative boost converter from a standard positive buck converter]]
+====== Implementing a negative buck regulator ======
+{{:modular_synthesizers:normal_buck.png?300}}
+{{:modular_synthesizers:negative_buck.png?300}}
+===== The Parallel Universe of Negative Input Voltagess =====
+[[https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/The-Parallel-Universe-of-Negative-Input-Voltages.pdf|The Parallel Universe of Negative Input Voltages]]
+By John Betten and Brian King suggests using a UCC3813 with an external switch mosfet and also provides a circuit to adjust the feedback voltage to make the reference work properly.
+{{:modular_synthesizers:parallel_negative_fig3.png?500}}
+It is (according to me) a bit easier if we rewrite the circuit and remove some compensation capacitors like this:
+{{:modular_synthesizers:parallel_negative_fig3_better.png?500}}
 ===== Risks and other considerations =====
 There are also some risks that needs some investigation before this can be deemed a good way forth.
@@ Line 61: / Line 84: @@
   * Higher impact by offset-voltages
   * Higher price
+  * Better to pick a positive-in-dual-rail-out available solution?