YOTUBE VIDEO TUTORIAL ON MC34063/33063
Dave Jones EEVblog You tube video takes you step-by-step through designing a DC-DC converter using the venerable MC34063. And then he build it and checks the performance.
HERE'S A DATASHEET FOR THE MC34063C from Silicon Link

An online calculator is here and a typical breadboard BELOW:
​PLEASE FILL OUT THE SURVEY FORM ON THE BOTTOM OF THIS WEB PAGE...THANKS

MC34063A-MC33063 development aid

This is a simple design tool using the equations from the MC34063A/MC33063 data sheet an application note that allows you to calculate component values for the MC34063A/MC33063 simple switcher chip. It displays the appropriate schematic diagram (step-up, step-down, or inverting) and checks for current and voltage limits. Feedback resistors are chosen from standard component values so that the output is as close to desired value as possible. The actual nominal value is an output of the data set. Typical input capacitor value is about 100uF; all capacitors need to be low ESR types. A fast Schottky diode should be sufficIent for a current needed, 1N5818, 1N5819, 1N5820 and alike will do just fine.

1: The polarity reversal. 2: Boost. 3: The step-down. Three typical circuit, the automatic calculation of the external components parameters
to use: enter the parameters you want in the left central box, then click the "Calculate and refresh schematic" button to calculate automatically all relevant external components parameters and the corresponding standard circuit drawings, the design of dc-dc circuit of interest.
Warning: If you enter the parameters of more than MC34063 capability or absolute maximum rating limit, it will automatically pop up a warning window to remind you to change them.
Special input : To design a polarity reversal circuit with a negative sign in front of the numbers of input or output voltage, for example,-5v.

This is a dc-dc power conversion IC (MC34063A), the application is relatively broad, generic inexpensive ( and easy to purchase with multiple semiconductor suppliers). Polarity inversion efficiency up to 65%, boost efficiency up to 90% step-down efficiency up to 80%, conversion efficiency and operating frequency is proportional to the filter capacitor.

In addition, the output power is mainly, such as> 250 ~ 300ma through external expansion of the outboard power transistor to increase the current using bipolar or MOSFETS

External components nominal meaning and value of the formula:

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

Ct ( timing capacitor ) : determine the internal operating frequency. Ct =4.0^-5 * Ton, (operating frequency)

Ipk = 2 * Iomax * T / toff

Rsc ( limited to flow resistance): determine the output current. Rsc = 0.33/Ipk

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

Co (filter capacitors): Determine the output voltage ripple factor, Co = Io * ton / Vp-p (ripple factor)

Fixed value parameters:

Vce sat = 1.0V ton / toff = (Vo + Vf-Vimin) / (Vimin-Vce sat) Vimin: instability in the input voltage when the minimum

Vf = 1.2V fast switching diode forward voltage drop

Attention in practical applications:

1:For Fast switching diode one can choose a IN4148, however designs that require high efficiency must use IN5819 family depending on output current levels

2: MC34063 output/inout voltage can not exceed 40V.

3: This code was designed by (c) Nomad Systems 2001,http://www.nomad.ee/micros/mc34063a/ and slightly edited and modified from ELECTRONIC PRODUCTS MAGAZINE ONLINE http://www.electronicproducts.com/DC-DC_Circuit_Calculator.aspx.