Power circuit without using inductors - Page 1
Forum section: electronics / projects

author: sagnikbasu
author_rank: Contributor
timestamp: February 03, 2017, 07:39:43 am
content: Most of the power circuit today use inductors for voltage conversion. Can we design one for negative dc -dc voltage conversion without using any kind of inductors ?Can charge pump be considered for power circuit applications ?

author: KhronX
author_rank: Frequent Contributor
timestamp: February 03, 2017, 07:54:30 am
content: www.intersil.com/content/dam/Intersil/documents/icl7/icl7660.pdfhttps://datasheets.maximintegrated.com/en/ds/ICL7660-MAX1044.pdf... But don't expect a lot of power out of themThat being said -http://electronics.stackexchange.com/questions/216094/why-are-charge-pumps-only-used-for-low-current-applications

author: Codebird
author_rank: Regular Contributor
timestamp: February 03, 2017, 10:07:49 am
content: There are a few ways. You don't see them very often because they are just inferior in most ways to inductors.Inductors: Compact, efficient, the modern solution in most circumstances.Capacitor charge pumps: Efficient, but only practical for low current.And the old-school ways, from before SMPS was practical:Motor-generator sets: Bulky, noisy, inefficient, unreliable.Battery switching: Bulky, inefficient, needs frequent servicing.Vibrator-transformer: The archaic version of the SMPS, and it still uses inductors. Used to be used in a lot of car radios to power valve circuitry.Electrostatic mechanical with motor drive: Used for generating crazy-high voltages at miniscule current.

author: David Hess
author_rank: Super Contributor
timestamp: February 03, 2017, 09:07:40 pm
content: The common alternative is an inverter where the transformer is not used for energy storage; this has the advantage of being lower noise than a switching converter. Big charge pumps using big capacitors and power transistors are also possible.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 04, 2017, 01:38:34 am
content: http://www.mmech.com/transformers

author: jbb
author_rank: Super Contributor
timestamp: February 04, 2017, 01:39:28 am
content: Note also that charge pumps can be less flexible than inductor-based designs.Normally, a charge pump delivers some rational gain. Typical examples are 2, -1, 3 etc. (minus some small voltage drops). This is quite efficient. You transfer energy from a capacitor with voltage VA into a capacitor with voltage VB, where A is a little more than B. The averageconductionpower loss Pond will be related to the average current Iavg. Pcond = Iavg * (VA-VB).Hoever, if you really need arbitrary voltage output, it can be done (I think by adjusting duty cycles). So VA >> VB. This means Pcond is large, and the converter is less efficient.If you need to operate in unusual environments (e.g. inside a large magnetic field such as MRI machine), it may be possible to use air-cored inductors.It is also possible to create multi-level switched capacitor converters which can deliver gains in the form of N / M, where N and M are integers. This allows for more output voltage levels with adequate efficiency, but requires more complex circuitry.