Notebook Power Car Adapter 19 Volt

No Comments »

Car cigarette lighter output DC voltage is 12 V, even when the engine is running will not exceed 13 .8 V, 19 V voltage lower than the normally required of notebook computers. The boost converter voltage conversion, the basic circuit shown in Figure 1, which consists of power switch T, diode D, the energy storage inductor L, and filter capacitor C The inductance constantly charge and discharge, the induced voltage is added to the resulting output voltage on the power supply voltage higher than the voltage provided by the car cigarette lighter.
Diagram Circuit:

(1) S conduction, D, cut-off: the input DC power UIN IIN current pathway formed by the inductance coil L and switch S DC power charging the inductor, the inductance L of the current linear increase in electrical energy to magnetic energy stored in the coil. At this point, the diode D is reverse biased, and output load current IOUT from the energy stored in the capacitor C, as shown in Figure 2 (a) below.

(2) S off: D conduction due to the inductance L of the current can not jump, induced in the coil shown by a very sexy raw voltage. Therefore, the polarity of the induced voltage is left negative right being. The diode D into forward state, the original through the diode D in S during the conduction of the energy stored in the inductor coil to the capacitor C and load RL. C at this stage, the energy charge in the next S period ending provided to the load RL.
The boost converter in the power switch S, one in the state of switch power MOSFET tube. Gate with a series of pulse power tube in the state and off alternately, changing the ratio of off time, you can adjust the size of the output voltage. Suppose that a cycle t, t = tON when the positive pulse, pulse width modulation pulse was sent to the gate of power transistor K conduction; when t = M1 is turned OFF (tOFF), modulation pulse sent to the K tube into the zero volt or negative bias, S in a closed state.

Author : Anonymous

Source : 182e.com

Lead Acid Battery Desulfator Schematic

No Comments »

This is my first printed circuit board battery
desulfator. The unit is pretty small about 2.5″ x 2″ in size. I laid
out the circuit last week and the printed boards arrived today.

It took me a about two hours to assemble and test the first unit. Oddly
enough everything worked perfect. The pulsing sounds good (you can
hear it whistle), the components are not over heating, I am able to
pulse at 180mA while the other desulfators are only doing 60mA. At
this point I’m just going to confirm a few more short tests then start
selling these units. They will go for $50 each and I’ll post them up
for sale next week. You can write a comment to this post if you think
you want one. These units should do a good job of restoring neglected
lead acid and Ni-CD chemistries.

Originally uploaded by mikeysklar

High Voltage Parallel Programmer AVR

1 Comment »

AVR has two different programming modes called Parallel Programming Mode (Parallel Mode) and Serial Downloading Mode (ISP mode).

At the Parallel Mode, the device to be programmed is put on the programmer’s socket and +12 volts programming voltage is required to its RESET pin. Communicating between the programmer and the device is done in parallel programming commands, so that the programing speed is two times faster than ISP mode. This programming mode is used to pre-program many devices or/and ISP mode cannot use due to the board design. However, most programmers except STK500 seem not to support this programming mode. Using High voltage parallel programmer can recovery wrong fuse bit setting.

Schematics Download :

  1. Circuit Diagram for Parallel/HVS Programmer
  2. Socket Converters for Parallel Programmer
  3. Circuit Diagram for 8/14pin HVS Programmer

Software Download :

  1. AVRPP.EXE(Win32) & Source

[Link]

USB Battery Charger for AA NiMH and NiCd

2 Comments »
usb battery Charger

usb battery Charger

usb Battery charger schematic

usb Battery charger schematic

The charger in this project is designed to charge two AA NiMH or NiCd cells of any capacity (as long as they are the same) at about 470mA. It will charge 700mAh NiCds in about 1.5 hours, 1500mAh NiMHs in about 3.5 hours, and 2500mAh NiMHs in about 5.5 hours. The charger incorporates an automatic charge cut-off circuit based on cell temperature, and the cells can be left in the charger indefinitely after cut-off. Read the rest of this entry »

keep looking »