Jensen567
(Jensen567)
October 6, 2017, 2:05pm
128
There are certainly plenty of high powered Boost-Buck controllers out there, but many require 4 external MOSFETs which makes space a problem. Using some super small surface mount FETs it might be possible to build something in the 30mm range. LTC3780 comes to mind here.
I’m willing to bet the MP8632 would output beyond 13V by a bit, similar to how the TPS61088 will actually max out around 13.7V instead of 12.5 like the datasheet says. We do tend to operate a lot of things outside of specs here. Haha.
Texas_Ace
(Texas_Ace)
October 6, 2017, 3:25pm
129
Jensen567:
There are certainly plenty of high powered Boost-Buck controllers out there, but many require 4 external MOSFETs which makes space a problem. Using some super small surface mount FETs it might be possible to build something in the 30mm range. LTC3780 comes to mind here.
I’m willing to bet the MP8632 would output beyond 13V by a bit, similar to how the TPS61088 will actually max out around 13.7V instead of 12.5 like the datasheet says. We do tend to operate a lot of things outside of specs here. Haha.
Yeah, those FET’s really eat up the space which would already be tight without them. Thats what makes these chips so attractive. Plus the lack of FET’s reduces the complexity which is always good for small designs.
Schoki
(Schoki)
October 7, 2017, 8:34pm
130
Maybe I can get an ATTiny13A on the MP3431 board, for biscotti-HD. To control the IC I would use the method used in the H2-C.
Agro
(Agro)
October 7, 2017, 8:51pm
131
How about ATTiny85 for e-switch?
Though either would be lovely…
Schoki
(Schoki)
October 7, 2017, 8:58pm
132
The 85 isn’t available in a package small enough to fit the underside of the board, I need 3x3mm, even 4x4mm is too big.
Lexel
(Lexel)
October 7, 2017, 9:07pm
133
Schoki:
First try on a 1-mode Buck-Boost converter for 2-3AA or 1 LiIon cell:
It uses a TPS63020. You have to calculate max current yourself (see page 13 in the datasheet), but it can do more than 800mA, even worst case. The current can be programmed via one resistor. There’s a jumper as well to choose between normal mode and low current high efficiency mode (see figures 10 and 11 in the datasheet).
Which parts list for this one
I need it fot 1.4A UV LED with 4.1V forward voltage in 17mm
Agro
(Agro)
October 7, 2017, 9:21pm
134
OK, I thought you meant the usual SOIC-8. Anyway, there are many great uses. :+1:
Though I think there are uses for 20+ mm variants with e-switch too.
Schoki
(Schoki)
October 8, 2017, 12:21am
135
Forgot that, the inductor is 1.5uH.
But I haven’t tested the circuit myself, so I just can hope it works. I will check the pinout one more time. I can recommend some Opamps, but I need the input voltage range for that. To get 1.4A, your resistor R3 should be as close to 5932.2 Ω as possible. Less resistance for less current, more resistance for more current.
Scientist
(Scientist)
October 7, 2017, 10:34pm
136
I too would like to build a UV light. Looking for a boost driver for 2x26650 to get 15V 1A to LED. Doesn’t need anything except on/off.
Lexel
(Lexel)
October 13, 2017, 2:27am
137
Schoki:
Forgot that, the inductor is 1.5uH.
But I haven’t tested the circuit myself, so I just can hope it works. I will check the pinout one more time. I can recommend some Opamps, but I need the input voltage range for that. To get 1.4A, your resistor R3 should be as close to 5932.2 Ω as possible. Less resistance for less current, more resistance for more current.
Input is a single cell 3.7V
this 20Mhz one OK?
http://www.mouser.de/ProductDetail/Texas-Instruments/OPA322AQDBVRQ1/?qs=sGAEpiMZZMuUbyQTl9BuV63CpDOSJaNbsqa6U%2FwQSlo%3D
Schoki
(Schoki)
October 13, 2017, 12:47pm
138
Yes this OpAmp will do it. Due to the 2mV maximum offset the current could be between 1.3-1.5A.
L4M4
(L4M4)
October 13, 2017, 1:10pm
139
If you only want on/off you can just use one of those buck converters from AliExpress.
I use one too for my 3*26650 light with a 100W COB in front.
Lexel
(Lexel)
October 13, 2017, 3:33pm
140
Schoki
(Schoki)
October 14, 2017, 12:14pm
141
Take the OPA365, the microchip parts seem to have a really high input offset drift when the supply voltage changes.
Lexel
(Lexel)
October 27, 2017, 5:13pm
142
Schoki:
First try on a 1-mode Buck-Boost converter for 2-3AA or 1 LiIon cell:
It uses a TPS63020. You have to calculate max current yourself (see page 13 in the datasheet), but it can do more than 800mA, even worst case. The current can be programmed via one resistor. There’s a jumper as well to choose between normal mode and low current high efficiency mode (see figures 10 and 11 in the datasheet).
could you share that board?
eh4
(eh4)
October 22, 2017, 4:23am
144
Kinda crying out in the wilderness here, but I need a high discharge FET drive that will allow these five conditions simultaneously;
- always on momentary signaling switch,
-adjustable frequency and duty cycle strobe only,
-momentary only,
- adjustable thermal step down,
ability to lock out programmability with
closed solder junction.
Jensen567
(Jensen567)
October 22, 2017, 4:36pm
145
Sounds more like you need custom firmware instead of custom hardware. Any of the BLF FET drivers should support that hardware wise.
Jassim
(Jassim)
October 22, 2017, 6:31pm
146
Can you Recommend a 17mm Driver (single cell) for xhp35 ?
Schoki
(Schoki)
October 22, 2017, 6:50pm
147
I currently try to make one. PCB is nearly finished, but I need to find an ATTiny25v rev. E in qfn package. I maybe will order from different shops, maybe some have the revision E.