48kHz/2kV Sine wave frequency divider - Page 1
Forum section: electronics / projects

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: September 27, 2014, 03:11:12 pm
content: I need to setup an easy way to divide a 48kHz, 2kV sine wave by a factor of 10. The circuit would need to be high impedance and efficient. I would eventually like to make this variable at some point but not needed now. I have a couple ideas rattling around my brain but wanted to throw this out there for more ideas.

author: Marco
author_rank: Super Contributor
timestamp: September 27, 2014, 03:31:56 pm
content: What's the load? Does the frequency divided signal have to be a sine too? What's the amplitude of the output supposed to be?

author: SeanB
author_rank: Super Contributor
timestamp: September 27, 2014, 03:43:31 pm
content: Just how big a ceramic transducer are you driving? It probably would be best to generate the 4.8kHz using a small transformer, or a repurposed CCFL inverter transformer.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: September 27, 2014, 03:50:23 pm
content: The load is between 1M and 10M. This is a low current HV reference signal. It needs to stay sinusoidal. The amplitude is 2kV but can vary as much as 20%. The circuit is operating now with a DC input between 1V (Min) and 12V (Max) which gives me a variable amplitude on the output between approximately 500V - 2kV. I can drive loads as low as 100K with some amplitude loss (Minimal), but that was just for my initial testing.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: September 27, 2014, 03:57:03 pm
content: Quote from: SeanB on September 27, 2014, 03:43:31 pmYeah, I am playing with a few of the CCFL inverters, all of the ones I have are around 36kHz to around 50kHz.

author: Richard Head
author_rank: Frequent Contributor
timestamp: September 28, 2014, 10:22:35 am
content: I would look at using a capacitive voltage divider. The top cap can be quite a small value (but high voltage) and the lower one much larger (by a factor of the voltage division ratio). The cap divider can feed an op-amp to buffer and amplify the signal. Will the phase shift be a problem?If you need a DC averaging circuit then use an op-amp in a precision rectifier configuration after the amplifier.For safety sake place a Zener across the lower cap of the capacitive divider in case it gets disconnected accidently.Dick

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 28, 2014, 10:53:50 am
content: Quote from: Richard Head on September 28, 2014, 10:22:35 amHe wants to divide the frequency, not the amplitude.

author: SeanB
author_rank: Super Contributor
timestamp: September 28, 2014, 12:00:08 pm
content: Probably best to get a non diode split LOPT and use that, driving it with a larger tuning capacitor so as to get it to resonate at a lower frequency. Probably will be a 4u7 1kV cap on the primary though.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 28, 2014, 07:52:45 pm
content: Why would you want to divide frequency?Dividing voltage versus dividing frequency is akin tohttp://www.xkcd.com/1425/Tim

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: September 28, 2014, 09:46:22 pm
content: Quote from: SeanB on September 28, 2014, 12:00:08 pmI mocked something up similar to your suggestion, seems to work, needs a bit of tweaking but I am in no rush. Thanks SeanB!