MAX77928 datasheet(32/88 Pages) AD

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10A 3:1/2:1/1:1 Switched-Capacitor

Direct Charger for 1S Li-Ion Battery

MAX77928

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To enable the feature, IIN_REG_TRACK_EN needs to be set to 1. Also, input current sense relies on ADC; therefore,

ADC and the input current channel must be enabled.

The debounce time for each IIN_REG[6:0] tracking depends on the period of each ADC burst conversion and how many

conversions are counted (programmable by IIN_TRACK_CNT_NUM[3:0]), or it can be calculated as ((CONV_NUM[1:0]

x Number of channels enabled + 1 dummy) x 1ms + 0.4ms + INTERVAL[1:0]) x IIN_TRACK_CNT_NUM[3:0]. For

example, if CONV_NUM[1:0] = 8 samples, Number of channels enabled = 9, INTERVAL[1:0] = 10ms,

IIN_TRACK_CNT_NUM[3:0] = 1, Debounce time for IIN_REG_TRACK = ((8 samples x 9 channels + 1 dummy) x 1ms +

0.4ms + 10ms) x 1 = 83.4ms.

Each time IIN_REG[6:0] is lowered by the auto-tracking feature, an IIN_REG_TRACK_INT interrupt is generated.

Protection Features

Input and Output Overvoltage Lockout (VIN OVLO and VOUT OVLO)

The IC provides input overvoltage lockout (VIN OVLO) and output overvoltage lockout (VOUT OVLO) to protect the

internal power stage. When VVIN is higher than VVIN_OVLO, or VVOUT is higher than VVOUT_OVLO, the SCC stops

operation, and the state goes to the Error state. A VIN_OVP_INT or VOUT_OVP_INT interrupt is generated. The

VIN_OVP_S or VOUT_OVP_S status bit is set.

Threshold of VIN OVLO is programmable by VIN_OVP_TH[1:0] and it automatically adjusts for different conversion ratio

(3:1/2:1/1:1 mode). Threshold of VOUT OVLO is programmable by VOUT_OVP_TH bit. Debounce time is programmable

by VIN_OVP_DEG and VOUT_OVP_DEG, respectively.

VEXT1 and VEXT2 Overvoltage Lockout (VEXT1 OVLO and VEXT2 OVLO)

The IC also provides VEXT1 overvoltage lockout (VEXT1 OVLO) and VEXT2 overvoltage lockout (VEXT2 OVLO) to

protect the downstream device. When VVEXTx is higher than VVEXT_OVLO, VEXTx_DRV pulls low to turn off the switch.

A VEXTx_OVP_INT interrupt is generated. VEXTx_OVP_S status bit is set.

Threshold of VEXTx OVLO is programmable by VEXTx_OVP_TH[2:0]. Debounce time is programmable by

VEXTx_OVP_DEG[1:0].

Battery (BATP – BATN) Overvoltage Lockout (VBATT OVLO)

If the battery voltage is too high during charging, the IC provides a battery (BATP – BATN) overvoltage lockout (VBATT

OVLO). When VBATP – VBATN is higher than VBATT_OVP, the SCC stops operation and the state goes to the Error state.

A VBATT_OVP_INT interrupt is generated.

Threshold of VBATT OVLO is programmable by VBATT_OVP_TH[6:0]. Debounce time is programmable by

VBATT_OVP_DEG.

Overcurrent Protections (CHGR OCP and RVSBST OCP)

The IC provides overcurrent protections which trigger when VPMID/N – VVOUT > IOCP_FWD (programmable by

CHGR_OCP[3:0]) in the forward/charging direction or VVOUT – VPMID/N > IOCP_RVS (programmable by

RVSBST_OCP[3:0]) in the reverse/discharging direction, where N is the conversion ratio. Overcurrent protections help

detect hard short quickly and protect the power stage. The SCC stops operation and state goes to Error state. A

CHGR_OCP_INT interrupt or RVSBST_OCP_INT interrupt is generated. Debounce time of the overcurrent protections

can be programmed by CHGR_OCP_DEG[2:0] and RVSBST_OCP_DEG[2:0], respectively.

Reverse Current Protection (CHGR RCP)

In forward/charging operation, when the input voltage is set lower than N (ratio) x VVOUT, current can flow from battery

to input. The IC provides a reverse current protection feature to disable the SCC when VVOUT – VPMID/N > IRCP

(programmable by CHGR_RCP[2:0]). A CHGR_RCP_INT interrupt is generated. Debounce time can be programmed by

CHGR_RCP_DEG[2:0].

Input Current Overcurrent Protection (IIN OCP)

The IC senses the input current at INFET for IIN OCP and IIN UCP. For both forward and reverse directions, when the

input current is higher than IIN_OCP (programmable by IIN_OCP[5:0]), the SCC stops operation and state goes to Error

state. An IIN_OCP_INT interrupt is generated. Debounce time can be programmed by IIN_OCP_DEG[1:0].

MAX77928 Datasheet(PDF) 32 Page - Analog Devices

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