Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

UC3842 BASED DC-DC Converter

Status
Not open for further replies.
N

nishu's

Junior Member level 2
Joined
May 10, 2012
Messages
24
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Activity points
1,467
Please take a look at attached schematic and tell me if its going to work or not, If not what corrections are required.

its basically a Boost converter with following specification
1. Input DC BUS IS : 5.8 - 9V
2. Output: 9V @ 3A

SIGNAL MEANING:
a> DC BUS: 5.8 - 9 V
b> 9V_SHUTDOWN: DISABLE SWITCHING OF UC3845
c> 9V_OUTPUT_OFF: DISCONNECTS -9V_SUPPY PORT FROM GND PORT
d> u9V_CUR_SENSE: OVER CURRENT AND SHORT CIRCUIT PROTECTION USING
MICRO-CONTROLLER.

5v-9v.png

every suggestion is welcomed
 

Your inductor is 10mH. It is common to use a much smaller value, below 1mH.

Your Q5 icon appears upside-down.

Check orientation of Q6, whether it's right side up.
 
Corrected: i changed inductor to 330uH and Q5 was indeed misplaced drain should be connected to inductor. I am not sure whats wrong with Q6 as it was placed to cutoff output when UC3842 is not switching disabling input voltage to reach output, so i cant point it out.
 

The name "-9V_SUPPLY" is confusing. It seems that it is a -9V supply. Its name should be like "GND(9V)"

- - - Updated - - -

R44(1K) is too low. Minimum Rt specified on the Rt/Ct graph (datasheet) is 3k.
 
am not considering component values for now as am in process of pcb design, so any help regarding misplaced component or layout would be a great.

- - - Updated - - -

thanks for correction, do you think anything else is misrouted.
 

There should be a capacitor between pin 7 & 5 of the IC. (power supply bypass capacitor)
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top