X3100 Datasheet, PDF (3/40 Pages) Xicor Inc. – 3 or 4 Cell Li-Ion Battery Protection and Monitor IC

X3100/X3101 – Preliminary Information
Cell Voltage Balancing Control (CB1-CB4):
These outputs are used to switch external FETs in order
to perform cell voltage balancing control. This function
can be used to adjust individual cell voltages (e.g.
during cell charging). CB1–CB4 can be driven high
(Vcc) or low (Vss) to switch external FETs ON/OFF. When
using the X3101, the CB4 pin can be left unconnected,
or the FET control can be used for other purposes.
Current Sense Inputs (VCS1–VCS2):
A sense resistor (R_SENSE) is connected between VCS1
and VCS2 (Figure 1). R_SENSE has a resistance in the
order of 20mΩ to 100mΩ, and is used to monitor current
flowing through the battery terminals, and protect
against over-current conditions. The voltage at each end
of R_SENSE can also be monitored at pin AO.
Over-charge Voltage detect Time control (OVT):
This pin is used to control the delay time (T_OV)
associated with the detection of an over-charge
condition (see section “Over-charge Protection” on page
13).
Over-discharge detect/release time control (UVT):
This pin is used to control the delay times associated
with the detection (T_UV) and release (T_UVR) of an over-
discharge (under-voltage) condition (see section “Over-
discharge Protection” on page 15).
Over-current detect/release time control (OCT):
This pin is used to control the delay times associated
with the detection (T_OC) and release (T_OCR) of an over-
current condition (see section “Over-Current Protection”
on page 18).
Analog Output (AO):
The analog output pin is used to externally monitor
various battery parameter voltages. The voltages which
can be monitored at AO (see section “Analog
Multiplexer Selection” on page 20) are:
– Individual cell voltages
– Voltage across the current sense resistor (R_SENSE)^.
This voltage is amplified with a gain set by the user in
the control register (see section “Current Monitor
Function” on page 20.)
The analog select pins pins AS0–AS2 select the desired
voltage to be monitored on the AO pin.
Analog Output Select (AS0–AS2):
These pins select which voltage is to be multiplexed to
the output AO (see section “Sleep Control (SLP)” on
page 10 and section “Current Monitor Function” on
page 20)
Serial Input (SI):
SI is the serial data input pin. All opcodes, byte
addresses, and data to be written to the device are input
on this pin.
Serial Output (SO):
SO is a push/pull serial data output pin. During a read
cycle, data is shifted out on this pin. Data is clocked out
by the falling edge of the serial clock. While CS is HIGH,
SO will be in a High Impedance state.
Note: SI and SO may be tied together to form one line
(SI/SO). In this case, all serial data communication with
the X3100 or X3101 is undertaken over one I/O line.
This is permitted ONLY if no simultaneous read/write
operations occur.
Serial Clock (SCK):
The Serial Clock controls the serial bus timing for data
input and output. Opcodes, addresses, or data present
on the SI pin are latched on the rising edge of the clock
input, while data on the SO pin change after the falling
edge of the clock input.
Chip Select (CS):
When CS is HIGH, the device is deselected and the SO
output pin is at high impedance. CS LOW enables the
SPI serial bus.
Over-charge Voltage Protection/Load Monitor
(OVP/LMON):
This one pin performs two functions depending upon
the present mode of operation of the X3100 or X3101.
—Over-charge Voltage Protection (OVP)
This pin controls the switching of the battery pack charge
FET. This power FET is a P-channel device. As such,
cell charge is possible when OVP/LMON=V_SS, and cell
charge is prohibited when OVP/LMON=V_CC. In this
configuration the X3100 and X3101 turn off the charge
voltage when the cells reach the over-charge limit. This
prevents damage to the battery cells due to the
application of charging voltage for an extended period of
time (see section “Over-charge Protection” on page 13).
REV 1.1.8 12/10/02
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Characteristics subject to change without notice. 3 of 40