Based on MT3608 card-type, plug-in adjustable buck-boost power module

The shape and hole position are adapted to the perforated board with adjustable voltage boosting and bucking modules for electronic games.
 
1. "Seller Show" explains
the basic parameters:
Input: 2~24V
Output: 2~28V
Current: 2A, maximum
type: step-up, step-up and step-down
Size: first version 31x17MM, revised 32x17MM
Highlights: one lithium battery, passed Setting the feedback resistor can output the corresponding voltage
 
. Starting point: Considering that on-site board production takes a long time and affects the progress, it is faster to build a simple circuit on a hole.
The picture shows two placement effects on a 4x6CM hole.
 
One is to stick it flat on the board, align the holes with the perforated board, and connect them with pin headers or wires.
The other one is inserted upside down on the board, with three pin headers soldered on the left side, occupying a little more space than a three-terminal voltage regulator chip.
The three-terminal voltage regulator tube can only step down the voltage, while the module can step up or step down the voltage. It can be said that the advantages are quite obvious.
 
2. Circuit description:
By adding capacitor C2 and inductor L2 to the circuit provided in the official manual, it can become a voltage regulating circuit that can both boost and step down.
The reference voltage of FB pin is 0.6V, and the output voltage formula is: 0.6*(1+R1/R2)
R2 is generally selected as 1K to facilitate calculation of multiples.
Assume that the output voltage requires 12V, substitute the formula to reversely calculate R1 = (12V / 0.6V) -1K = 19K.
The module on the cover is configured with 20K and 1K to achieve an output of 12.6V.
 
3. Instructions for use
The potentiometer pad is modified to a rectangular shape to facilitate welding. If the chip 0805 resistor
is available, give priority to selecting the chip resistor by calculating the resistance value. If there is no other way, use the potentiometer.
Generally, R2 has a fixed resistance value of 1K, and different resistance values ​​can be connected in series or parallel through the pads of R1 and R3 to achieve the resistance value you want.
 
When the resistors R1 and R3 are placed in the blue box, they are in a parallel relationship. The resistance of the two resistors in parallel is R=(R1*R3) / (R1+R3).
 
When the blue box is placed in the position of the resistor R1, they are in a series relationship. Before welding, the right side needs to be The connection between the two pads must be cut off, otherwise it will be invalid.
 
The second physical piece R2=1K, connected in series through 2.2K and 5.1K resistors to form 7.3K, the output voltage is 5V
. 5V is a common voltage, 2.2K and 5.1K are also commonly used resistors.
7.3K is a rare variety in the mall
. The silk screen printing of R2 and R3 is reversed, and the component welding is correct.
 
Set the output voltage to 5V and compare it with the measurement results. The no-
 
load ripple is less than 20mV, with an average of 15mV (a bargain, the data is for reference only).
 
If you only need to boost the voltage, then the inductor L2 Do not solder. Do not solder capacitor C2.
Change the two pads of C2 to short-circuit and directly connect, or use a 0 ohm resistor instead of C2.
 
4. Regarding welding,
you can use Teppanyaki or hand-soldering with a soldering iron.
If you want to hand-solder, please refer to the numerical sequence.