Data Sheet

ADP5090

Rev. C | Page 15 of 21

Voltage Threshold (V)

4

6.98

3.01

5.49

4.53

4.1

6.98

2.94

5.6

4.42

4.2

7.15

2.87

5.62

4.32

4.3

7.15

2.8

5.76

4.22

4.4

7.32

2.74

5.9

4.12

4.5

7.32

2.7

5.9

4.02

4.6

7.32

2.61

6.04

3.92

4.7

7.5

2.55

6.19

3.83

4.8

7.5

2.5

6.2

3.74

4.9

7.5

2.49

6.34

3.74

5

7.5

2.43

6.34

3.65

5.1

7.68

2.37

6.49

3.57

5.2

7.68

2.32

6.49

3.48

Table 6. Power Path Working State

Power Path

Power Condition

Main Boost

BAT Switch

SYS Switch

BACK_UP_M1

BACK_UP_M2

Without

Backup Battery

Asynchronous

Off

Off

Off

Off

Synchronous

On

On

Off

Off

Disabled

On

On

Off

Off

With Backup

Battery

Synchronous

On

Off

On

On

Asynchronous

Off

Off

On

On

Disabled

Off

Off

On

On

Disabled

Off

Off

Off

Off

POWER PATH WORKING FLOW

Figure 32 shows the power switches structure when the backup

primary battery is implemented. When the BACK_UP voltage

is higher than the BAT voltage, the SYS switch prevents the

BACK_UP primary battery from charging the BAT pin.

Meanwhile, the BAT offset avoids input source charging

BACK_UP primary battery. Table 6 shows the power path

working state.

Figure 32. Power Switches Structure

CURRENT-LIMIT AND SHORT-CIRCUIT PROTECTION

The boost regulator in the ADP5090 includes current-limit

protection circuitry to limit the amount of positive current

flowing through the low-side boost switch. It is a cycle-by-cycle,

three level peak current-limit protection with a third level of

100 mA (typical).

Although there is no current limit at the SYS and BAT pins, it is

recommended to limit the system load current to lower than

800 mA. The total resistance of the SYS switch and the BAT

switch (1.03 Ω, typical), generates a voltage drop when the

system load sinks a large current from BAT. It is necessary to

consider the internal resistance of the storage elements

connected to the BAT pin.

The BACK_UP power path current limit of 400 mA (typical)

protects the primary battery sinking large current. When the

current from the BACK_UP pin is higher than the current limit,

the BACK_UP switches turn off.

THERMAL SHUTDOWN

In the event that the ADP5090 junction temperature rises above

125°C, the thermal shutdown (TSD) circuit turns off the switch

between the BAT pin and the SYS pin to prevent the damage of

energy storage at a high ambient temperature. The boost operation

is also terminated. A 15°C hysteresis is included, allowing the

ADP5090 to return to operation when the on-chip temperature

drops below 110°C. When coming out of TSD, the boost regulator

and the energy storage controller resume the functions.

BAT

+

–

+

–

BSTO

BACK_UP

BACK_UP_M1

D1

BACK_UP_M2

SYS_SWITCH

BAT_SWITCH

HS

LS

SW

SYS

GATE

DRIVER

GATE

DRIVER