ADP5091ACPZ-2-R7 datasheet(19/28 Pages) AD

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Data Sheet

ADP5091/ADP5092

Rev. A | Page 19 of 28

BACKUP AND BAT SELECTION THRESHOLD

To determine when to enable the BACK_UP function, the switch

threshold on the BAT pin must be set by using external resistors at

SETBK pin. When the BAT voltage is lower than the SETBK

threshold, the internal BACK_UP_Mx control circuit automatically

selects the high voltage terminal as the SYS power source. Figure 42

shows the VSETBK falling threshold voltage given by Equation 3.

BK1

SETBK

INT

REF

BK2









(3)

The ADP5091/ADP5092 have an internal resistor, RSETBK_HYS =

115 kΩ (typical), to program the hysteresis, given by

Equation 4.

SETBK_HYS

SETBK



(4)

where RE is the equivalent resistor of the four external

configuration resistor dividers.

Considering the quiescent current consumption, the sum of the

resistors that comprise the resistor divider (RSETBK_HYS, RBK1, and

RBK2) must be greater than 6 MΩ, that is,

RSETBK_HYS + RBK1 + RBK2 > 6 MΩ

(5)

The equivalent resistor of the four external configuration resistor

dividers (RE) is equivalent to the paralleling value of the three

resistor dividers.

BAT

TERM_REF

REF

SETBK

VINT_REF

TERM

RSETBK_HYS

RSETSD_HYS

RSD1

RPG_HYST

RPG1

RBK1

RTERM1

RSD2

RPG2

RBK2

RTERM2

TRM

TERM_REF

BAT

TERM

CONTROL

SETSD

PGOOD

SETPG

SETHYST

Figure 42. ADP5091/ADP5092 Program Paramater Setting

BATTERY OVERCHARGING PROTECTION

To prevent rechargeable batteries from being overcharged and

damaged, the battery terminal charging threshold (VBAT_TERM) must

be set by using external resistors. Figure 42 shows the VBAT_TERM

rising threshold voltage given by Equation 6.



















TERM2

TERM1

REF

INT

TERM

BAT

(6)

Considering the quiescent current consumption, the sum of the

resistors must be more than 6 MΩ, that is,

RTERM1 + RTERM2 ≥ 6 MΩ

(7)

The battery terminal charging threshold is given by VBAT_TERM_HYS,

which is internally set to the battery terminal charging threshold

minus an internal hysteresis voltage denoted by VBAT_TERM_HYS.

When the voltage at the battery exceeds the VBAT_TERM threshold,

the main boost regulator disables. The main boost starts again

when the battery voltage falls below the VBAT_TERM_HYS level. When

input energy is excessive, the VBAT pin voltage ripples between

the VBAT_TERM and the VBAT_TERM_HYS levels.

BATTERY DISCHARGING PROTECTION

To prevent rechargeable batteries from being deeply discharged

and damaged, the battery stop discharging threshold (VSETSD)

must be set by using external resistors. Figure 42 shows the

VSETSD falling threshold voltage given by Equation 8.

SD1

SETSD

INT

REF

SD2









(8)

The ADP5091/ADP5092 have an internal resistor, RSETSD_HYS =

115 kΩ (typical), to program the hysteresis, given by Equation 9.

SETSD_HYS

SETSD



(9)

Considering the quiescent current consumption, the sum of the

resistors that comprise the resistor divider (RSETSD_HYS, RSD1, and

RSD2) must be more than 6 MΩ, that is,

RSETSD_HYS + RSD1 + RSD2 ≥ 6 MΩ

(10)

The equivalent resistor of the three external configuration

resistor dividers (RE) is equivalent to the paralleling value of the

three resistor dividers.

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