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DC-DC Circuit MC34063A Online Calculator

Category: App description 1: Polarity is reversed. 2: Boost. 3：Depressor

Automatic calculation of peripheral component parameters for three typical circuits

How to use: Just enter the parameter you want in the left middle box, then click the “Calculate and refresh circuit diagram” button, it will automatically give all relevant peripheral component parameters and corresponding standard circuit drawings to make the design dc— The dc circuit is intelligent and efficient.

The nominal meaning of the peripheral components and the calculation formula for their values:

$$Vout(output voltage)=1.25V(1+R1/R2)$$

Ct: Determine the internal working frequency. Ct=0.000 004*Ton (working frequency)

$$Ipk=2 * Iomax * T/toff$$

Rsc (current limiting resistor): Determines the output current. Rsc=0.33/Ipk

Lmin (inductance): Lmin = (Vimin-Vces) * Ton / Ipk

Co (filter capacitor): determines the output voltage ripple factor, Co = Io * ton / Vp - p (corrugation coefficient)

Fixed value parameters:

Vces=1.0V ton/toff=(Vo+Vf-Vimin)/(Vimin-Vces) Vimin: the minimum value when the input voltage is unstable

Vf=1.2V fast switching diode forward voltage drop

Usage example

Input data: input voltage 35v; output voltage 220v; output current 240ma; output voltage ripple coefficient 65mv (pp); operating frequency 240khz

Perform calculations and refresh the circuit diagram:

Ct=141 pF

Ipk=3097 mA

Rsc=0.097 Ohm

Lmin=39 uH

Co=117 uF

R=180 Ohm

R1=1k R2=91k (115V)

Note

About the warning: If the parameter you entered exceeds the limit of 34063, it will automatically pop up a warning window to remind you to change them.

Special input: To design the polarity reversal circuit, add a negative sign in front of the input or output voltage number, such as -5v.

Input voltage range: 3-40V

Note in practical applications:

1: IN4148 can be used for fast switching diodes. IN5819 must be used when high efficiency is required!

2:34063 can withstand the voltage, that is, the sum of the absolute value of the input and output voltage can not exceed 40V, otherwise it can not work safely and stably.

Other manual parameters:

parameter name symbol unit MC34063(Motorola, USA) ＣＷ34063(domestic) IRM03A(Japan Sharp Corporation)
Input voltage Vin V 2.5～40V 2.5～40V 2.5～40V
Output voltage Vout V 1.25～40V 1.25～40V 1.25～40V
Maximum output current Iomax A 1.5A 1.5A 1.8A
Maximum working frequency f kHz 0.1～100KHZ 0.1～100KHZ 0.1～100KHZ
power P W 1.25W 1.25W 0.9W
Operating temperature Ta Degree 0～70度 0～70度 0～70度