MAX1535A Datasheet, PDF (20/39 Pages) Maxim Integrated Products – Highly Integrated Level 2 SMBus Battery Charger

Highly Integrated Level 2 SMBus
Battery Charger
Table 3. ChargerSpec()
BIT
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Command: 0x11
BIT NAME
CHARGER_SPEC
CHARGER_SPEC
CHARGER_SPEC
CHARGER_SPEC
SELECTOR_SUPPORT
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
DESCRIPTION
Returns a zero for version 1.1
Returns a 1 for version 1.1
Returns a zero for version 1.1
Returns a zero for version 1.1
Returns a zero, indicating no smart-battery selector functionality
Returns a zero
Returns a zero
Returns a zero
Returns a zero
Returns a zero
Returns a zero
Returns a zero
Returns a zero
Returns a zero
Returns a zero
Returns a zero
The default charge-current setting at POR is 128mA.
Thus, the first time a MAX1535A powers up, the charge
current is regulated at 128mA. Anytime the battery is
removed, the ChargeCurrent() register returns to its
POR state.
ChargeVoltage() (POR: 0x4B00)
The ChargeVoltage() command uses the Write-Word
protocol (Figure 3). The command code for
ChargeVoltage() is 0x15 (0b00010101). The 16-bit
binary number formed by D15–D0 represents the
charge-voltage set point in millivolts. However, the res-
olution of the MAX1535A is 16mV in setting the charge
voltage; the D0–D3 bits are ignored as shown in Table
7. The D15 bit is also ignored. Figure 7 shows the map-
ping between the charge-voltage set point and the
ChargeVoltage() code. All codes requesting charge
voltage greater than 19.200V result in a voltage over-
range, limiting the charge voltage to 19.200V. All codes
requesting charge voltage below 1024mV result in a
voltage set point of zero, which terminates charging.
The default charge-voltage setting at POR is 19.200V.
Thus, the first time a MAX1535A powers up, the charge
voltage is regulated at 19.200V. Anytime the battery is
removed, the ChargeVoltage() register returns to its
POR state.
AlarmWarning()
The AlarmWarning() command uses the Write-Word pro-
tocol (Figure 3). The command code for AlarmWarning()
is 0x16 (0b00010110). AlarmWarning() sets the
ALARM_INHIBITED status bit in the MAX1535A if D15,
D14, D13, D12, or D11 of the Write-Word protocol equals
1. Table 8 summarizes the AlarmWarning() command’s
function. The ALARM_INHIBITED status bit remains set
until the battery is removed, a ChargerMode() command
is written with the POR_RESET bit set, or new
ChargeCurrent() and ChargeVoltage() values are written.
As long as ALARM_INHIBITED = 1, the MAX1535A
switching regulator remains off.
InputCurrent() (POR: 0x0080)
The InputCurrent() command uses the Write-Word pro-
tocol (Figure 3). The command code for InputCurrent()
is 0x3F (0b00111111). The 16-bit binary number
formed by D15–D0 represents the charge-current set
point in milliamps. However, the resolution of the
MAX1535A is 256mA in setting the charge current; the
D0–D6 bits are ignored as shown in Table 9. The D13,
D14, and D15 bits are also ignored. Figure 8 shows the
mapping between the input-current set point and the
InputCurrent() code. All codes requesting input current
greater than 11.004A result in an input-current over-
range, limiting the input current to 11.004A. All codes
requesting input current between 1mA and 256mA
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