ISL78610 Datasheet, PDF (29/98 Pages) Intersil Corporation – Multi-Cell Li-Ion Battery Manager

COMPONENT
C₁ (2 ea)
C₂ (4 ea)
R₁ (4 ea)
ISL78610
TABLE 6. DAISY CHAIN COMPONENT VALUES FOR BOARD LEVEL IMPLEMENTATION
DAISY CHAIN DATA RATE
TOLERANCE
500kHz
250kHz
125kHz
5%
100pF
220pF
470pF
5%
220pF
470pF
1nF
1kΩ
1kΩ
1kΩ
62.5kHz
1nF
2.2nF
1kΩ
VREF
ADC
ISL78610
TEMPREG
VCC
10M
EXT4
R₁
R₂
10k
10k
C₁
10nF
RT
R₁₂
FIGURE 50. CONNECTION OF NTC THERMISTOR TO INPUT EXT4
COMPONENT
R₁
R₂
Thermistor
C₁
TABLE 7. COMPONENT FUNCTIONS AND DIAGNOSTIC RESULTS FOR CIRCUIT OF FIGURE 50
FUNCTION
DIAGNOSTIC RESULT
Protection from wiring shorts to external HV
connections.
Open: Open-wire detection
Short: No diagnostic result
Measurement high-side resistor
Open: Low input level (over-temperature indication)
Short: High input level (open-wire indication).
Open: High input level (open-wire indication).
Short: Low input level (over-temperature indication)
Noise Filter. Connects to measurement ground Open: No diagnostic result.
VSS.
Short: Low input level (over-temperature indication)
External Inputs
The ISL78610 provides 4 external inputs for use either as general
purpose analog inputs or for NTC type thermistors.
The arrangement of the external inputs is shown in Figure 50
using the ExT4 input as an example. It is important that the
components are connected in the sequence shown in Figure 50,
e.g., C₁ must be connected such the trace from this capacitor’s
positive terminal connects to R₂ before connecting to R₁. This
guarantees the correct operation of the various fault detection
functions.
Each of the external inputs has an internal pull-up resistor, which
is connected by a switch to the VCC pin whenever the TEMPREG
output is active. This arrangement results in an open input being
pulled up to the V_CC voltage.
Inputs above 15/16 of full scale are registered as open inputs and
cause the relevant bit in the Over-Temperature Fault register, along
with the OT bit in the Fault Status register to be set, on condition of
the respective temperature test enable bit in the Fault Setup
register. The user must then read the register value associated
with the faulty input to determine if the fault was due to an open
input (value above 15/16 full scale) or an over-temperature
condition (value below the External Temperature Limit setting).
The function of each of the components in Figure 50 is listed in
Table 7 together with the diagnostic result of an open or short
fault in each component.
Typical Applications Circuits
Typical applications circuits are shown in Figures 51 to 57.
Table 8 on page 38 contains recommended component values.
All external (off-board) inputs to the ISL78610 are protected
against battery voltage transients by RC filters, they also provide
a current limit function during hot plug events. The ISL78610 is
calibrated for use with 1kΩ series protection resistors at the cell
inputs. V_BAT uses a lower value resistor to accommodate the
V_BAT supply current of the ISL78610. A value of 27Ω is used for
this component. As much as possible, the time constant
produced by the filtering applied to V_BAT should be matched to
that applied to the cell 12 monitoring input. Component values
given in Table 8 produce the required matching characteristics.
Submit Document Feedback ₂₉
FN8830.1
June 16, 2016