This constant current module is
useful for charging batteries or powering LEDs from a DC power source or any
application which requires constant voltage or constant current. Other
applications include filament power and electromagnet power,
 Fault detection, current limit,
short circuit protection, reverse polarity, low voltage input protection
Can be used as a simple CC/CV
battery charger for lead acid or lithium batteries
Input voltage from 6 volts up to
36 volts (must be at least 0.5V higher than the output voltage required)
Can be used for high efficiency
current control of LED and LED strings
User adjustable output voltage and
current limit, down to 25mV output
Flexible voltage reducing DC/DC
converter with current up to 5 amps
Huge compliance voltage swing, up to 32V, down to 25mV
to maintain a constant current with a changing load resistance
Can be used to safely charge supercapacitors at high
rates.
| |
Quantity |
1-9 |
10-99 |
100-999 |
1000+ |
| PST-DCCP constant current DC/DC step down converter |
 |
$27 |
$25 |
$22 |
$19 |
PST-DCCP-XX-YY factory adjusted,
specify maximum
voltage and current settings required |
|
$32 |
$29 |
$25 |
$22 |
Optional barrel socket to screw terminal adapters
|
Price |
ZHJX002
5.5 x 2.1 mm barrel socket |
$2.50 each
|
SDY-C52M
5.5 x 2.1 mm barrel plug |
$2.50 each
|
Optional DIN mounting
hardware
 (not including the rail) |
$3.50
|
|
| PST-DCCP |
Specifications |
| Input voltage: |
6V to 36V input |
| Output user adjustable: |
0.025V to 36V output (input voltage must
be at least 6 volts, and 0.5V higher than the output) |
| Peak output current: |
Up to 5 Amps, current limit is
user-adjustable |
| Continuous output current |
3.5 Amps |
| Isolation |
Non-isolated, common ground. To operate in
constant current mode
both the positive and the negative output wires must
be used |
| Adjustment method |
Pots accessible on the top of the unit.
The pot labeled W103 adjusts the output voltage limit.
The pot labeled
W102 adjusts the output current limit.
Do not try to adjust the output
current while connected to the battery under charge, interaction with the
battery will make it impossible to get something repeatable. |
| Efficiency |
Up to 96% efficient with 5V or higher
output, up to 87% with 3.3V output |
| Form |
Potted module with flying leads |
| Battery charging |
Works as a constant current - constant
voltage battery charger. Will fold back the voltage to match the user
adjustable maximum charge current, then when the voltage reaches the user
adjusted maximum charge voltage it lets the current taper down. There is no LED
indication when the battery is fully charged, but the battery can be left on
the charge circuit indefinitely without being overcharged.
It is suitable
for Lead Acid, Lithium Ion, Lithium Polymer, and Lithium Iron Phosphate
batteries. See chart below. |
| Adjustment method |
Two multi-turn pots, these have many
turns, so don't get discouraged, you can't damage the pots by turning them too
far |
| LED |
Green = Input power on
Blue = Constant
voltage mode
Red = Constant current mode
Note: the DC/DC converter will
work with inputs down to 3V, but the LEDs
do not operate until the input
raises to 5VDC. |
| Temperature range |
-10° to +60°C |
| Connections |
Wire leads 20AWG, 5 inches, 130mm long
Input: black and red
Output: black and yellow |
| Dimensions |
1.5 x 3.36 x 0.82 inches, 38 x 85 x 21 mm
including flange |
| Weight |
2.8 oz, 80 grams |
| Mounting holes |
3.0 inches center to center, 0.10 inches
diameter
76 mm center to center, 2.4 mm diameter |
User notes and applications.
NOTE: even though this
is a common ground DC converter BOTH GROUNDS must be attached, one to the
source negative and one to the load negative. It is OK if the source and load
negatives are connected together.
Battery Charger
- First determine the highest voltage that the battery will
float at
- For lead acid batteries the voltage will be 2.25-2.33
Volts/cell in series, or 13.4-14V for a 6-cell 12V Battery
- For lithium ion batteries the voltage is 4.2 Volts/cell
in series
- For lithium iron phosphate batteries the voltage is 3.65
Volts/cell in series.
- Next set the maximum voltage on the PST-DCCP
- Attach a power source at lest 1 volt higher than the
desired maximum charge voltage to the red and black leads
- Attach a volt meter to the output leads (yellow and
black)
- Adjust the potentiometer labeled W103 to give the desired
voltage
- Then set the maximum charge current desired
- You cannot adjust the output current while connected to
the battery. Instead use the following protocol.
- Set your multimeter to the highest current setting,
usually 10 or 20 Amps
- Attach the output leads of the PST-DCCP to the ammeter
leads
- Note: this shorts the PST-DCCP, but it is OK, since
the PST-DCCP can handle a short circuit. Don't try this with other power
sources such as batteries, power supplies, and DC converters.
- Adjust the current setpoint potentiometer (labeled W102)
to give the maximum current output that you require, less than 5 Amps
- Remove the ammeter
- Alternately you can select a resistor by the following
equation R= Vmax/Imax
- Attach the output of the PST-DCCP to the resistor in series
with the ammeter
- The resistor will get hot, so watch out
- Adjust the output current
| Chemistry |
Number of cells in series |
Nominal pack voltage |
Maximum charge voltage |
| Lead Acid |
1 |
2V |
2.3V |
| |
2 |
4V |
4.6V |
| |
3 |
6V |
6.9V |
| |
4 |
8V |
9.2V |
| |
5 |
10V |
11.5V |
| |
6 |
12V |
13.8V |
| |
7 |
14V |
16.1V |
| |
8 |
16V |
18.4V |
| |
9 |
18V |
20.7V |
| |
10 |
20V |
23V |
| |
11 |
22V |
25.3V |
| |
12 |
24V |
27.6V |
| |
13 |
26C |
29.9V |
| Lithium Ion |
1 |
3.6V or 3.7V |
4.2V |
| |
2 |
7.2V or etc. |
8.4V |
| |
3 |
10.8V |
12.6V |
| |
4 |
14.4V |
16.8V |
| |
5 |
18V |
21V |
| |
6 |
21.6V |
25.2V |
| |
7 |
25.2V |
29.4V |
| LiFePO 4 |
1 |
3.2V |
3.65V |
| |
2 |
6.4V |
7.3V |
| |
3 |
9.6V |
11V |
| |
4 |
12.8V |
14.6V |
| |
5 |
16V |
18.3V |
| |
6 |
19.2V |
21.9V |
| |
7 |
22.4V |
25.6V |
| |
8 |
25.6V |
29.2V |
Supercapacitor Charger
- Charging a supercapacitor through a standard resistance can
take a long time due to the RC time constant. The constant current converter
will raise the voltage continuously as the capacitor is filled, until the
highest charge voltage is obtained without overshooting the maximum set
voltage.
- First determine the highest voltage that the supercapacitor
or ultracapacitor is rated for under continuous use.
- This is usually 1.25V to 4V per capacitor in series,
depending on the manufacturer, check their data sheet
- Next set the maximum voltage on the PST-DCCP as follows:
- Attach a power source at lest 1 volt higher than the
desired maximum charge voltage (red and black leads)
- Attach a volt meter to the output leads (yellow and black
leads)
- Adjust the potentiometer labeled W103 to give the desired
voltage
- Set the maximum charge current desired as follows
- Set your multimeter to the highest current setting,
usually 10 or 20 Amps
- Attach the output leads of the PST-DCCP (black and yellow
leads) to the ammeter
- Note: this shorts the PST-DCCP, but it is OK, since
the PST-DCCP can handle a short circuit. Don't try this with other power
sources such as batteries, power supplies, and DC converters.
- Adjust the current setpoint potentiometer (labeled W102)
to give the maximum current output that you require, less than 5 Amps
- Remove the ammeter
LED controller
- Determine the highest voltage that the LED can accept
- This will be 1.6V to 32V depending on the color and the
number of LEDS in series
- This is found on the LED data sheet
- Determine the electrical current that you want to operate at
- Some LEDs have current limiting resistors built-in. In
this case the voltage is the critical parameter
- Other LEDS are current controlled. In this case current
is the critical parameter.
- For high efficiency it is better to have the DC converter
control the current, then no power is lost in the current limiting resistor
- Set the maximum voltage on the PST-DCCP
- Attach a power source at lest 1 volt higher than the
desired maximum LED voltage (black and red leads)
- Attach a volt meter to the output leads
- Adjust the potentiometer labeled W103 to give the desired
voltage
- Set the maximum charge current desired
- Set your multimeter to the highest current setting,
usually 10 or 20 Amps
- If you want current lower than 500mA, use the high
current setting first, then the mA setting for fine tuning
- Attach the output leads (black and yellow) of the
PST-DCCP to the ammeter leads
- Note: this shorts the PST-DCCP, but it is OK, since
the PST-DCCP can handle a short circuit. It will just reduce the voltage to
stay within its output power parameters. Don't try this with other power
sources such as batteries, power supplies, and DC converters.
- Adjust the current setpoint potentiometer labeled W102 to
give the maximum current output that you require, less than 5 Amps
- Remove the ammeter
Laser diode controller
- Determine the highest voltage that the laser diode can accept
- This will be 1.2V to 5V depending on the wavelength of
the laser
- This is found on the laser diode packaging or data sheet
- Determine the electrical current that you want to operate at
- Laser diodes are current controlled. In this case current
is the critical parameter.
- Set the maximum voltage on the PST-DCCP
- Attach a power source at lest 1 volt higher than the
desired maximum Laser diode (black and red leads)
- Attach a volt meter to the output leads
- Adjust the potentiometer labeled W103 to give the desired
peak voltage
- Set the maximum charge current desired
- Set your multimeter to the highest current setting,
usually 10 or 20 Amps
- If you want current lower than 500mA, use the high
current setting first, then the mA setting for fine tuning
- Attach the output leads (black and yellow) of the
PST-DCCP to the ammeter leads
- Note: this shorts the PST-DCCP, but it is OK, since
the PST-DCCP can handle a short circuit. It will just reduce the voltage to
stay within its output power parameters. Don't try this with other power
sources such as batteries, power supplies, and DC converters.
- Adjust the current setpoint potentiometer labeled W102 to
give the maximum current output that you require, less than 5 Amps
- Remove the ammeter
- It is a good idea to measure the current with the laser
diode in place, in series with the ammeter to verify that the amperage is
correct under the final load
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