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Detailed Operation of the Evaluation Board

5.4 STAT-1 and STAT-2 Indicators

The LM3658 has two open-drain outputs to indicate the charge status of the LM3658, as shown in

Table 2.

These two outputs can be connected to LEDs or to General Purpose I/Os (GPIO). On the LM3658

evaluation board, STAT-1 is connected to a red LED and STAT-2 is connected to a green LED.

Table 2. STAT-1 and STAT-2 Indicators

STAT-1 (CHG) STAT-2 (EOC) Condition

Off Off Power-down, charging is suspended or interrupted

On Off Pre-qualification mode, CC and CV charging

Off On Charge is completed

On On Bad battery (Safety timer expired) or LDO mode

5.5 Battery Temperature Monitoring

The LM3658 is equipped with a battery thermistor interface to continuously monitor the battery

temperature by measuring the voltage between the T

pin and ground. Internal to the LM3658 are two

comparators that set a upper limit of 2.5V and a lower limit of 0.5V in which charging is allowed. If the

voltage at T

pin is outside of this window, charging is suspended. On the LM3658 evaluation board, the

pin is connected to a 10 kΩ resistor.

5.6 LDO Mode of the LM3658-B

By removing the 10 kΩ resistor and leaving the T

pin floating, the LM3658-B assumes there is no battery

present and goes into LDO mode if CHG-IN pin is connected to an AC adaptor. In LDO mode, the

LM3658 provides up to 1A of current at BATT pin. The LDO mode is not possible when operating from the

USB

PWR

input. The jumper located next to R8 can be removed to observe the LDO mode function on the

LM3658-B eval board. Note that removing the R8 jumper on the LM3658 and LM3658-A evaluation board

causes an effective battery overtemperature condition and the charge current will turn off.

SNVA181E–September 2006–Revised April 2013 AN-1517 LM3658 Evaluation Kit

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