PIC Projects
WiFi - ESP8266
Doorbell with SD / EEPROM
SD FAT16/32 for .bmp
LCD TFT Egg Timer
LCD TFT Oscilloscope
SD Talking Clock
SD Sound Recorder,
    FAT32 wav Player
LED Thermometer
LED Egg Timer
LCD Egg Timer

Frequency Counters
TFT 10MHz
100KHz For PC
1MHz For PC
8 Digits LED 50 MHz
Scope Screen Display
LCD Module 10MHz
6MHz for Android
USB PIC18F2550
USB TFT display BMP
USB DS18B20 Sensor
USB Thermometer
USB Counter
USB Meter
USB Oscilloscope
USB Input-Output
USB 16x2 LCD

COM & LPT Ports
MCP3201 on LPT
Serial TFT Text
Serial Inputs Outputs
Serial Port LCD
Analogue Signal to LPT
MCP3201 on Serial Port
Serial Thermometer
Analogue Signal to Serial
LCD Display on LPT
Serial Thermostat

Others
Water Softener
HP Stream 7 docking
3.7V to 5V
Solar Charger

Infrared Decoder
PIC Music

Code Lock
Code Lock with LCD
HOME MOBILE Technical Tips

3.7V to 5V CONVERTER

Low power 5V or 9V from 3.7V lithium ion cell. The 5V can power the projects that use LCD, output current up to 10mA. The 9V version can power most digital multimeters that run on PP3, output current up to 5mA. The output voltage is regulated by the zener diode and the output current is limited by the value of L1.

Circuit Description
See also Technical Tips

The hex inverter 4049 CMOS are used as a free running oscillator. BC337 charges the coil when it's on, and when it's off the coil dumps its charge via the diode 1N4148 into the output capacitor.
When output voltage exceeds the zener voltage BC337 is switched on and stops the oscillator until output voltage drops below the zener voltage.
Table for selecting components.

Output R1 R2 R3 Z1 L1
5V 22K 220R 470R 4.7V 220 - 680 uH
9V 10K 2K2 100K 9.1V 1 - 2.2 mH

Cmos 4049UB can also be 4049B.
Equivalent to BC337 can be used.
Coil can be the smallest physical size available.
Resistors are 5% tolerance.

 





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Comments and questions

Copy the number from the picture It stops net-robots from adding comments.



13.02.2015 - 12:48
Name: Zarif
Comment: can I use this with NI-CAD?