MAX17059EVKIT# Maxim Integrated, MAX17059EVKIT# Datasheet - Page 8

• Manufacturer Part Number: MAX17059EVKIT#
• Description: Power Management IC Development Tools MAX17059 Eval Kit
• Manufacturer: Maxim Integrated
• Series: MAX17058, MAX17059r

Specifications of MAX17059EVKIT#

• Part # Aliases: 90-BCA1K#E00

For best performance, the host microcontroller must
measure battery temperature periodically, and compensate
the RCOMP ModelGauge parameter accordingly, at least
once per minute. Each custom model defines constants
RCOMP0, TempCEach custom model defines constants
RCOMP0 (default is 0x97), TempCoUp (default is -0.5),
and TempCoDown (default is -5.0). To calculate the new
value of CONFIG.RCOMP:
// T is battery temperature (degrees Celsius)
if (T > 20) {
}
else {
}
Figure 4. Increasing Empty Voltage Reduces Battery Capacity
Figure 5. ModelGauge Heals Error Automatically
RCOMP = RCOMP0 + (T - 20) x TempCoUp;
RCOMP = RCMOP0 + (T - 20) x TempCoDown;
60
50
40
30
20
10
0
-10mV
-20mV
3.0
0mV
0.1
RELAXATION TIME BEFORE INSERTION (MINUTES)
3.1
TARGET EMPTY VOLTAGE (V)
LONGER BATTERY RELAXATION
IMPROVES INITIAL ACCURACY
SOC ERROR
Temperature Compensation
1
3.2
VOLTAGE ERROR
3.3
10
C/3 LOAD
C/10 LOAD
3.4
100
1-Cell /2-Cell Li+ ModelGauge ICs
3.5
1000
0%
-5%
-10%
Most applications have a minimum operating voltage
below which the system immediately powers off (empty
voltage). When characterizing the battery to create a cus-
tom model, choose empty voltage carefully. As shown in
Figure
an accelerating rate as empty voltage increases.
To ensure a controlled shutdown, consider including
operating
on
shutting down at 3% or 5%. This utilizes the battery
more effectively than adding error margin to empty voltage.
When the battery is first inserted into the system, the
fuel-gauge IC has no previous knowledge about the
battery’s SOC. Assuming that the battery is relaxed, the
IC translates its first V
initial estimate of SOC. Initial error caused by the battery
not being in a relaxed state diminishes over time, regard-
less of loading following this initial conversion. While the
SOC estimated by the coulomb counter diverges, the
ModelGauge SOC converges, correcting error automati-
cally as illustrated in
lasting impact.
Any time the IC powers on or resets (see the
Register (0x18)
maximum of 16 V
resolution). OCV is ready 17ms after battery insertion,
and SOC is ready 175ms after that.
-10%
-5%
0%
some
MAX17058 /MAX17059
4, capacity unavailable to the system increases at
0
RELAXED ERROR
UNRELAXED SOC
AUTOMATICALLY OVER TIME
MODELGAUGE HEALS ERROR
TIME AFTER INSERTION (MINUTES)
margin
low
20
RELAXED SOC
section), it estimates that OCV is the
threshold
CELL
UNRELAXED ERROR
Impact of Empty-Voltage Selection
40
Figure
into
CELL
samples (1ms each, full 12-bit
REFERENCE SOC
Battery-Insertion Debounce
the
measurement into the best
60
5; initial error has no long-
of
fuel
SOC,
Battery Insertion
80
45%
30%
15%
0%
gauge
for
example,
VRESET
based
8