PS042

DS40237A-page 2

 2002 Microchip Technology Inc.

1.0

PRODUCT OVERVIEW

PowerCal is a comprehensive hardware platform that

supports configuration, verification, calibration and

production test of Microchip PowerSmart smart battery

systems. It operates under the control of Microchip’s

PowerTool Development/Test software interfaced to a

Windows PC.

The PowerCal board facilitates serial communication

between the PC and the SMBus interface on smart

batteries, providing a direct connection to both. Under

control of PowerTool, PowerCal performs loading and

verification of battery configuration parameters and 3D

cell models in PS40X EEPROM and OTP memory.

In addition, the PowerCal platform provides a complete

precision system for calibrating current, voltage and

temperature

measurements

in

a

smart

battery,

eliminating the need for expensive meters or power

supplies.

During calibration, the PowerCal board accurately

measures current, voltage and temperature and

compares these measured values to those reported by

the smart battery. Calibration values are then loaded

into the programmable storage and used by the chip to

compensate raw measurements made during normal

operation. Reported values from the PowerSmart IC

are therefore corrected to eliminate known, measured

errors.

The PowerCal platform accomplishes calibration with

programmable

load

and

precision

measurement

hardware so that a known, constant discharge current

is drawn from the battery pack. The programmable load

circuit is capable of drawing up 36W continuous

discharge power from the battery pack during calibra-

tion using natural-convection cooling. Higher discharge

currents are supported at reduced duty cycles, and/or

with forced-air cooling. In addition, there are provisions

for the user to add their own external charger or load,

at up to 10A.

The PowerCal board is designed to support both

development and test environments. Both RS-232 and

RS-485 interfaces are present so that the board can

operate with a stand-alone connection (RS-232) or with

a multidrop connection (RS-485) to the host PC. The

hardware supports up to 7 PowerCal boards interfaced

on a multidrop link from a PC COM port. As a result, up

to 28 boards can be interfaced on a single PC with 4

COM ports. PowerCal boards can fit in a DIN 6U rack

(2.25" board spacing); they can also be panel-

mounted.

Extensive safety features include production proven

EMI/ESD protection, optical isolation of the serial ports

and protective fuses. Fuses protect the device under

test, the PowerCal hardware and any connected

external charger or load. The board is implemented

using 4 layers with a dedicated ground plane. All I/O’s

are connected to bypass capacitors to earth ground.

2.0

GENERAL SETUP

The Microchip PowerCal platform is a very powerful,

versatile calibration, test and evaluation system. It can

be used in a variety of ways, as a single board in a

development environment and as a multi-board

system in a high volume production environment. The

instructions that follow will guide you through setup for

each of the features on the board. References to

modules refer to PCB products not yet assembled into

packs or connected to cells.

Power is provided to the board to the JP connector with

a 24V DC, 500 mA power supply wall adapter.

2.1

Connections

• JP – 24V DC power supply.

• TBP – pluggable terminal block alternate 24V DC

power supply (parallel connections with JP).

• TBS – pluggable terminal block for board-level

test I/Os (to be developed later).

• TBC – Support for future capability.

• TBB – pluggable terminal block for device under

test, module or pack (includes connections for cell

voltage measurement and programming voltage).

• PC – cell simulator port