Datasheet

TPS659110, TPS659112, TPS659113, TPS659116

SWCS049L –JUNE 2010–REVISED MARCH 2014

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8.3.3.12 Comparators: COMP1 and COMP2

The TPS65911 device has three comparators for system status detection/control. One comparator detects the

voltage at pin VCC7. When VCC7 > VMBHI, the comparator initiates a NO SUPPLY-to-OFF transition and the

VMBHI_IT interrupt is generated. When VCC7 < VMBLO, the comparator initiates an ACTIVE/SLEEP/OFF-to-

BACKUP transition. When both VCC7 and backup battery are below VBPNR, the NO SUPPLY state is entered.

Comparators COMP1 and COMP2 detect the voltage of VCCS. Programmbale comparator COMP1 is intended

for detecting if battery voltage is high enough for an OFF-to-ACTIVE transition of the TPS65911 device. For an

OFF-to-ACTIVE transition VCCS must be > VMBCH (main battery charged) and a level below the comparator

threshold prevents the power-up sequence. The threshold can be set from 2.5 to 3.5 V with 50-mV steps through

VMBCH_SEL. The comparator has debouncing so that VCCS must stay above VMBDCH (VMBCH – 0.1 V) for a

debouncing period of 61 µs. The comparator can be bypassed if the threshold selection is set to 0. The default

threshold is set in the boot configuration.

In a system with a multiple-cell battery, the battery level is sensed through an external resistor divider. The

TPS65911 device has an internal buffer at the VCCS input, which must be used with the external resistive

divider.

In a single-cell system, VCCS and VCC7 are connected directly to the battery. The VCCS input buffer can be

bypassed to minimize power consumption. The buffer bypass is controlled with the VMBBUF_BYPASS bit in the

boot configuration.

COMP2 is disabled by default and can be enabled by software. The comparator trigger generates an interrupt

which is programmable on the rising (VMBCH2_H_IT) or falling edge (VMBCH2_L_IT), hence the comparator

can be used for detecting high or low battery scenarios. COMP2 generates an interrupt for the host. In sleep

mode, this creates a wake-up interrupt for the host. In off mode, the comparator trigger generates a turn-on

event. In backup or no supply modes, the comparator is not active.

The COMP2 threshold can be set from 2.5 to 3.5 V with 50-mV steps. Enabling the comparator is done through

the voltage threshold selection bit VMBDCH2_SEL, which is set to 0 by default.

8.3.3.13 Watchdog

The watchdog has two modes of operation.

In periodic operation an interrupt is generated with a regular period defined by the WTCHDG_TIME setting. The

IC initiates WTCHDOG shutdown if the interrupt is not cleared within the period. The watchdog interrupt

WTCHDOG counter is reinitialized when NRESPWRON is low.

In interrupt mode the IC initiates WTCHDOG counter when interrupt is set pending and is cleared when interrupt

is cleared. If no interrupt is cleared before watchdog expiration within WTCHDG_TIME, the device goes to off

mode.

By default, periodic watchdog functionality is enabled with the maximum WTCHDG_TIME period.

Product Folder Links: TPS659110 TPS659112 TPS659113 TPS659116