Leader: Amos FriendHardware Specialist: Luke NoscheseSoftware Specialist: Jacob LongwillAssistant: Ryan Trump

Power SystemsBy: Team Leroy Jenkins

Understand the ProblemNimH BatteriesCharge and discharge graphsHardwareSoftwareSummaryReferencesQ&A

OverView

Power SystemsClean accurate power to respective

components Safeguard against destroying components with

too much powerUnderstanding power output of the batter as it

drainsDisplaying battery lifeUse on-board LED to change color depending

on battery life.

The Problem

Battery NiMH (Nickel-Metal Hydride)LM2940 or 4941 LDO Regulator (5v Volts)MCP1702 or 1700 LDO Regulator(3.3 Volts)2x 4.7KΩ5 Capacitors of different values

Components Needed

NiMH BatteryNickel–metal hydride

batteryDoes not have Memory

Effect as NiCd did7.2v battery

Output can go as high as ~9.5v when fully charged

3000mAh battery6-cellEach cell

1.2v3000mAh

Discharge Graph of full 7.2v NiMH

Single 1.2v cell charge graph

Single 1.2v cell discharge graph

Different groups have different 5v and 3.3v regulators

Use only two voltage regulators1 – 5v regulator1 – 3.3v regulator

3 outputsDirectly from Nimh battery5v output3.3v output

Hardware

Battery DisplayVoltage Divider

If full battery voltage is supplied it will destroy the port

Divide voltage in halfMultiply by 2 in code

To display correct voltage on LCD

Remember to ground the board and battery to a common ground

Large capacitor is needed after 5v regulator for rapid power drain from servo

Hardware Wiring

LM2940 LDO Regulator 5 VOLTS @ MAX 1

AMP MAX INPUT 26VLOW DROPOUT

VOLTAGE500mV @ 1A

LM4941 LDO Regulator5 VOLTS @ MAX 1

AMP MAX INPUT 26VLOW DROPOUT

VOLTAGE250mV @ .5A

MCP1700-3302 LDO Regulator3.3 VoltOperation range

2.5v-6vOutput current

250mALow Dropout Voltage

350 mV typical @ 250 mA (VOUT = 2.5V)

Looks similar to a transistor

MCP1702 LDO Regulator3.3 VoltOperation range

2.8v-13.2vMax out 250mA Low Dropout Voltage

625 mV typical @ 250 mA (VOUT = 2.8V)

Looks similar to a transistor

Flowchart for battery output

Software

Varibles#define VBMIN 500int VBATT;

FB_RGB_ENABLE;FB_RGB_ON;Call Batcheck In Forever Loop

Software Code

void BATCHECK(void)

ADCSC1 = 10; // start 11-bit ADC on PTD3

WAITFOR(ADCSC1_COCO); // wait for conversion complete (new technique)

VBATT = ((((ADCR * 500)/1023)*2));

if (VBATT >= VBMIN && VBATT < VBMIN*(3/2))

FB_RGB_BLUE = 0;

FB_RGB_GREEN = 1;

FB_RGB_RED = 0;

BatCheck

else if(VBATT < VBMIN)FB_RGB_BLUE = 1;FB_RGB_GREEN = 1;FB_RGB_RED = 0;motorDC = 0;

else

FB_RGB_BLUE = 1;FB_RGB_GREEN = 0;FB_RGB_RED = 1;

BatCheck Continued

Analog to Digital Converter

ADC Register

PROBLEM STATEMENT DISTRIBUTING PROPER VOLTAGE TO VARIOUS PARTS OF THE

SMART CAR MONITORING BATTERY STATUS

HARDWARE REQUIREMENTS/CONCEPTS INTERFACE

SOFTWARE DESIGN CODE

Summary

250 MA Low Quiescent Current LDO Regulator." Microchip Technology Inc. Microchip Technology Inc., n.d. Web. 11 Mar. 2014.

"ALIMENTAZIONE." ALIMENTAZIONE. N.p., n.d. Web. 11 Mar. 2014.

"L4941 Very Low Drop 1A Regulator." STMicroelectronics, n.d. Web. 11 Mar. 2014. "LM2940/LM2940C 1A Low Dropout Regulator." Texas Instruments. Texas

Instruments, n.d. Web. 11 Mar. 2014.

"Nickel–cadmium Battery." Wikipedia. Wikimedia Foundation, 28 Feb. 2014. Web. 11 Mar. 2014.

"PDIP | ChipKIT Development Platform." ChipKIT Development Platform. N.p., n.d. Web. 11 Mar. 2014.

"Voltage Divider." Wikipedia. Wikimedia Foundation, 03 JulY2014. Web. 11 Mar. 2014.

MCF51JM128 Reference Manual Notebook reference CET 335 lab 7 Analog to Digital Input

References

Any Questions?