X3101 datasheet(21/40 Pages) XICOR

21 / 40 page

X3100/X3101 – Preliminary Information

Characteristics subject to change without notice.

21 of 40

REV 1.1.8 12/10/02

www.xicor.com

of four input resistors to Op Amp OP1. The feedback

resistors remain constant. This ratio of input to feedback

resistors determines the gain. Putting external resistors

in series with the inputs reduces the gain of the ampliﬁer.

VCS1 and VCS2 are read at AO with respect to a DC

bias voltage of 2.5V. Therefore, the voltage range of

VCS12 and VCS21 changes depending upon the

direction of current ﬂow (i.e. battery cells are in Charge

or Discharge—Table 21).

Table 26. AO Voltage Range for VCS12 and VCS21

By calculating the difference of VCS12 and VCS21 the

offset voltage of the internal op-amp circuitry is

cancelled. This allows for the accurate calculation of

current ﬂow into and out of the battery cells.

Pack current is calculated using the following formula:

VOLTAGE REGULATOR

The X3100 and X3101 are able to supply peripheral

devices with a regulated 5VDC±0.5% output at pin

RGO. The voltage regulator should be configured

externally as shown in Figure 10.

The non-inverting input of OP1 is fed with a high

precision 5VDC supply. The voltage at the output of the

voltage regulator (VRGO) is compared to this 5V

reference via the inverting input of OP1. The output of

OP1 in turn drives the regulator pnp transistor (Q1). The

negative feedback at the regulator output maintains the

voltage

5VDC±0.5%

(including

ripple)

despite

changes in load, and differences in regulator transistors.

When power is applied to pin VCC of the X3100 or

X3101, VRGO is regulated to 5VDC±10% for a nominal

time of TOC+2ms. During this time period, VRGO is

“tuned” to attain a ﬁnal value of 5VDC±0.5% (Figure 2).

The maximum current that can ﬂow from the voltage

regulator (ILMT) is controlled by the current limiting

resistor (RLMT) connected between RGP and VCC. When

the voltage across VCC and RGP reaches a nominal

2.5V (i.e. the threshold voltage for the FET), Q2 switches

ON, shorting VCC to the base of Q1. Since the base

voltage of Q1 is now higher than the emitter voltage, Q1

switches OFF, and hence the supply current goes to zero.

Typical values for RLMT and ILMT are shown in Table 27.

In order to protect the voltage regulator circuitry from

damage in case of a short-circuit, RLMT ≥ 10Ω should

always be used.

Table 27. Typical Values for RLMT and ILMT

When choosing the value of RLMT, the drive limitations

of the PNP transistor used should also be taken into

consideration. The transistor should have a gain of at

least 100 to support an output current of 250mA.

Figure 10. Voltage Regulator Operation

4KBIT EEPROM MEMORY

The X3100 and X3101 contain a CMOS 4k-bit serial

EEPROM, internally organized as 512 x 8 bits. This

memory is accessible via the SPI port, and features the

IDLock function.

The 4kbit EEPROM array can be accessed by the SPI

port at any time, even during a protection mode, except

during sleep mode. After power is applied to VCC of the

X3100 or X3101, EEREAD and EEWRITE Instructions

Cell State

AO Voltage Range

VCS12

Charge

2.5V

≤ AO ≤ 5.0V

VCS12

Discharge

≤ AO ≤ 2.5V

VCS21

Charge

≤ AO ≤ 2.5V

VCS21

Discharge

2.5V

≤ AO ≤ 5.0V

Pack Current

VCS

–

()

() gain setting

()(current sense resistor)

----------------------------------------------------------------------------------------------------------

RLMT

Voltage Regulator Current Limit (ILMT)

Ω

250mA ± 50% (Typical)

Ω

100mA ± 50% (Typical)

Ω

50mA ± 50% (Typical)

VCC

RGC

RGP

RGO

Voltage

Reference

To Internal Voltage

Regulating Circuitry

Regulated

5VDC Output

RLMT

Un-Regulated

Input

Voltage

ILMT

Precision

X3100/X3101

OP1

5VDC

Tuning

VRGO

0.1

µF

X3101 Datasheet(PDF) 21 Page - Xicor Inc.

X3101 Datasheet(HTML) 21 Page - Xicor Inc.

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Datasheet Download

Link URL