Hi,
Well after my little handy Sparkgun breadboard PSU died (PCB traces ruined after many many repairs) I've decided to make one or two myself. Pretty simple, but as always, if I am going through the hassle of making my own PCB, I might as well see if I can add footprints for some 'extra's
Original board: SparkFun Electronics - Breadboard Power Supply 5V/3.3V
Nothing special, just an LM317 with selectable 3.3v/5v output. Only attaches to one power rail on the breadboard, and I usually use both (or at least ground on both rails, and power just a the top).
I can't say I do much in the way of analogue, but it would be nice to have a negative rail avaliable for opamp work. I am fully aware of using an AC supply to provide it, but I have a few 'wall warts' which range from 6-15V DC, and I don't want to be tied down to only being able to use just one. Also, for some higher current apps, say if I need 5v for an LCD backlight (up to 400mA), with an input of 12V thats a fair bit of heat on the regulator - I don't like heatsinks on my breadboard. This makes me think 'buck'.
I have a large number of parts available (left over from prototypes and work) so heres what I'm thinking:
-LDO regulator 700mA (so I can use a 6v PSU). + Charge pump 7660-like chip, with input selectable from 5v reg output, to my DC input. Thats positive 3.3v, 5v, and DC in (12v?) all high power. And negative, -5V, and -12v (both low power).
-The above but with a charge pump boost as well - got some tiny SOT23-5 ones. Input to both charge pumps (positive and negative) either 3.3v, or 5V from an LDO. That gives me positive: 3.3v, 5v, (and 10v low power). And negative rails of the same voltages, all at lower power. -10V available if the input to the negative CP comes from the positive one.
- Buck regulator, with 2-9v+ out (3.3v 5v, 6v presets), and a charge pump circuit tapped off this to provide the negative compliment. As its not using a 7660, the current output of the negative rail can easily reach 100mA with psuedo regulation.
Of course, the buck will add more noise to the output, but charge pumps aren't exactly 'quiet' either.
It all sounds rather complicated, but considering the IC's I have available, part count is remarkably low, with the largest parts being the jumpers for the settings. And the use of a 'boost charge pump' to get 5v from the LDO to 10V may seem redundant as the input power to my circuit will be 9-12V, but that would mean I could get +10V by using any input voltage from 6-15v.
I have seen plenty of idea's on the internet, but most are either linear regulators, with heatsinks, or biploar PSU's requiring >20V AC inputs. Few of which can be on a PCB which is mounted directly on the breadboard. So, any idea's? or would any one be interested in such a board? I have a habit of forgetting the KISS principle, but I have space on the PCB for some extra SMT footprints, so I can always just not populate those parts.
What do you guys use for your breadboard power?
ps. I haven't even mentioned using a boost converter with tapped inductors and charge pumps, that can take in 5v, and kick out any biploar voltage from +/-5 all the way to +/- 20V with around 12 components.
Well after my little handy Sparkgun breadboard PSU died (PCB traces ruined after many many repairs) I've decided to make one or two myself. Pretty simple, but as always, if I am going through the hassle of making my own PCB, I might as well see if I can add footprints for some 'extra's
Original board: SparkFun Electronics - Breadboard Power Supply 5V/3.3V
Nothing special, just an LM317 with selectable 3.3v/5v output. Only attaches to one power rail on the breadboard, and I usually use both (or at least ground on both rails, and power just a the top).
I can't say I do much in the way of analogue, but it would be nice to have a negative rail avaliable for opamp work. I am fully aware of using an AC supply to provide it, but I have a few 'wall warts' which range from 6-15V DC, and I don't want to be tied down to only being able to use just one. Also, for some higher current apps, say if I need 5v for an LCD backlight (up to 400mA), with an input of 12V thats a fair bit of heat on the regulator - I don't like heatsinks on my breadboard. This makes me think 'buck'.
I have a large number of parts available (left over from prototypes and work) so heres what I'm thinking:
-LDO regulator 700mA (so I can use a 6v PSU). + Charge pump 7660-like chip, with input selectable from 5v reg output, to my DC input. Thats positive 3.3v, 5v, and DC in (12v?) all high power. And negative, -5V, and -12v (both low power).
-The above but with a charge pump boost as well - got some tiny SOT23-5 ones. Input to both charge pumps (positive and negative) either 3.3v, or 5V from an LDO. That gives me positive: 3.3v, 5v, (and 10v low power). And negative rails of the same voltages, all at lower power. -10V available if the input to the negative CP comes from the positive one.
- Buck regulator, with 2-9v+ out (3.3v 5v, 6v presets), and a charge pump circuit tapped off this to provide the negative compliment. As its not using a 7660, the current output of the negative rail can easily reach 100mA with psuedo regulation.
Of course, the buck will add more noise to the output, but charge pumps aren't exactly 'quiet' either.
It all sounds rather complicated, but considering the IC's I have available, part count is remarkably low, with the largest parts being the jumpers for the settings. And the use of a 'boost charge pump' to get 5v from the LDO to 10V may seem redundant as the input power to my circuit will be 9-12V, but that would mean I could get +10V by using any input voltage from 6-15v.
I have seen plenty of idea's on the internet, but most are either linear regulators, with heatsinks, or biploar PSU's requiring >20V AC inputs. Few of which can be on a PCB which is mounted directly on the breadboard. So, any idea's? or would any one be interested in such a board? I have a habit of forgetting the KISS principle, but I have space on the PCB for some extra SMT footprints, so I can always just not populate those parts.
What do you guys use for your breadboard power?
ps. I haven't even mentioned using a boost converter with tapped inductors and charge pumps, that can take in 5v, and kick out any biploar voltage from +/-5 all the way to +/- 20V with around 12 components.
