I need a HV (250-300V) power supply to bias an avalanche photo-diode (current ~1 mA max). The spec sheet of the LT3420 says it can be used as a supply but there are no details. Is it possible to have it always charging? And not have the charging block turn on and off. Or should I try another IC? (LT3750?) Or something like figure 13 from here.
My name is Victor Khasiev, firstname.lastname@example.org. Can you tell us little be more about spec (input voltage, ripple ..) and details of application.
Hi Victor, thanks for the response. I’ve mostly just started the design, so specs are a bit fluid at the moment.
For the APD, I’ll need fairly low ripple… I’m thinking less than 100mV, but I’m not really sure. I’ve been looking at a different flyback controller chip. The LTC3803. That one looks more useful. As far as the input voltage. Yeah I don’t really like the max input to the LT3402 (and it’s kin) 24V might be a better input voltage.
What company you work for and what's expected annual usage of the controller? We need a formal spec to give you credible suggestions. You can contact me at email address as well.
Hi Victor. I thought this was email? Anyway the company I work for is Teachspin Inc.
(website at teachspin.com)
Unfortunately our volumes are very low. Maybe 10-50 units a year… it might not even turn into a product.
Say I attached a LTspice file. I tried designing this using a CCM, but I had to up the current and it looks to be DCCM. Is that typical for these types of flybacks? I don’t see how to make it different except with a much bigger inductor.
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The LTspice model you sent works. The operation mode of the flyback converter defined by the transformer inductance and output current. Other words at given inductance, flyback can be in a pulse skipping, DCM or CCM as output current increases.
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