X3100 Xicor, X3100 Datasheet - Page 20

• Manufacturer Part Number: X3100
• Description: 3 or 4 Cell Li-Ion Battery Protection and Monitor IC
• Manufacturer: Xicor

X3100/X3101 – Preliminary Information
REV 1.1.8 12/10/02
Table 24. Over-Current Protection Mode—Event Diagram Description (Continued)
MONITOR MODE
Analog Multiplexer Selection
The X3100 and X3101 can be used to externally monitor
individual battery cell voltages, and battery current.
Each quantity can be monitored at the analog output pin
(AO), and is selected using the analog select (AS0–AS2)
pins (Table 25). Also, see Figure 9.
Table 25. AO Selection Map
Current Monitor Function
The voltages monitored at pins VCS
used to calculate current flowing through the battery
terminals, using an off-board microcontroller with an A/D.
The internal gain of the X3100 or X3101 current sense
voltage amplifier can be selected by using the WCNTR
Notes: (1) This is the normal state of the X3100 or X3101. While in
AS2 AS1 AS0
H
H
H
H
L
L
L
L
Event
(3,4)
[3]
[4]
(2) VCS
H
H
H
H
L
L
L
L
this state Over-charge and Over-discharge Protection
conditions are periodically monitored (See “Periodic Pro-
tection Monitoring” on page 12.)
voltage of 2.5V (See section “Current Monitor Function”
on page 20).
The internal over-current release timer continues counting for T
1
— The device detects the load resistance has risen above 250k
— Voltages P+ and VCS
— The test current from pin OVP/LMON is stopped (I
— The device has now returned from the load monitor state
— The internal over-current release time timer begins counting down.
— Device is still in over-current protection mode.
— The internal over-current release timer times out, and VCS
— The device returns from over-current protection mode, and is now in normal operation mode.
— The discharge FET is automatically switched ON (UVP/OCP=Vss)—unless the status of UVPC has
— The status of the charge FET remains unaffected.
— Discharge of the battery cells is once again possible.
, VCS
H
H
H
H
L
L
L
L
been changed in the control register during the over-current protection mode.
2
V
VCELL
VCELL
VCELL
VCELL
VCS
VCS2–VCS
V
are read at AO with respect to a DC bias
SS
SS
(1)
1
–VCS
1
2
3
4
–VCELL
–VCELL
–VCELL
–Vss (VCELL
2
1
AO output
(VCS
(VCS
2
3
4
1
(VCELL
(VCELL
(VCELL
12
21
21
and VCS
)
)
(2)
return to their normal levels.
4
(2)
)
12
23
34
)
)
)
2
can be
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Event Description
Since the value of the sense resistor (R
(typically in the order of tens of m
resolution of various A/D converters may vary, the
voltage across R
internally with a gain of between 10 and 160, and output
to pin AO (Figure 9).
Figure 9. X3100/X3101 Monitor Circuit
Instruction to set bits CSG1 and CSG0 in the control
register (Table 14). The CSG1 and CSG0 bits select one
LMON
VCS
=0µA)
1
OCR
21
Voltage
Shifters
R
Level
R1
SENSE
Ω
is still below V
.
seconds.
R2
SENSE
R1
Characteristics subject to change without notice.
VCS
2.5V
Register
Cross-Bar
Config
Switch
2
Cell 1 Voltage
Cell 2 Voltage
Cell 3 Voltage
Cell 4 Voltage
CSG1 CSG0
( VCS
+
-
OC.
OP1
R2
Setting
Gain
1
and VCS
X3100/X3101
Over-Current
Protection
Ω
),
SPI
SENSE
I/F
2
and since the
) is amplified
) is small
S0
SCL
CS
SI
20 of 40
AS0
AS2
AS1
AO
P-