Datasheet

TAS5614LA

www.ti.com

SLAS846 –MAY 2012

OVERTEMPERATURE WARNING, OTW

The over temperature warning OTW asserts when the junction temperature has exceeded recommended

operating temperature. Operation at junction temperatures above OTW threshold is exceeding recommended

operation conditions and is strongly advised to avoid.

If OTW asserts, action should be taken to reduce power dissipation to allow junction temperature to decrease

until it gets below the OTW hysteresis threshold. This action can be decreasing audio volume or turning on a

system cooling fan.

UNDERVOLTAGE PROTECTION (UVP) AND POWER-ON RESET (POR)

The UVP and POR circuits of the TAS5614LA fully protect the device in any power-up/down and brownout

situation. While powering up, the POR circuit resets the overload circuit (OLP) and ensures that all circuits are

fully operational when the GVDD_X and VDD supply voltages reach stated in the Electrical Characteristics table.

Although GVDD_X and VDD are independently monitored, a supply voltage drop below the UVP threshold on

any VDD or GVDD_X pin results in all half-bridge outputs immediately being set in the high-impedance (Hi-Z)

state and FAULT being asserted low. The device automatically resumes operation when all supply voltages have

increased above the UVP threshold.

ERROR REPORTING

Note that asserting RESET low forces the FAULT signal high, independent of faults being present. TI

recommends monitoring the OTW signal using the system micro controller and responding to an overtemperature

warning signal by, e.g., turning down the volume to prevent further heating of the device resulting in device

shutdown (OTE).

To reduce external component count, an internal pullup resistor to 3.3 V is provided on both FAULT and OTW

outputs.

The FAULT, OTW, pins are active-low, open-drain outputs. Their function is for protection-mode signaling to a

PWM controller or other system-control device.

Any fault resulting in device shutdown is signaled by the FAULT pin going low. Likewise, OTW goes low when

the device junction temperature exceeds 125°C (see the following table).

Table 4. Error Reporting

FAULT OTW DESCRIPTION

0 0 Overtemperature (OTE) or overload (OLP) or undervoltage (UVP)

0 1 Overload (OLP) or undervoltage (UVP)

1 0 Junction temperature higher than 125°C (overtemperature warning)

1 1 Junction temperature lower than 125°C and no OLP or UVP faults (normal operation)

FAULT HANDLING

If a fault situation occurs while in operation, the device will act accordingly to the fault being a global or a channel

fault. A global fault is a chip-wide fault situation and will cause all PWM activity of the device to be shut down,

and will assert FAULT low. A global fault is a latching fault and clearing FAULT and restart operation requires

resetting the device by toggling RESET. Toggling RESET should never be allowed with excessive system

temperature, so it is advised to monitor RESET by a system microcontroller and only allow releasing RESET

(RESET high) if the OTW signal is cleared (high). A channel fault will result in shutdown of the PWM activity of

the affected channel(s). Note that asserting RESET low forces the FAULT signal high, independent of faults

being present. TI recommends monitoring the OTW signal using the system micro controller and responding to

an over temperature warning signal by, e.g., turning down the volume to prevent further heating of the device

resulting in device shutdown (OTE).

Product Folder Link(s): TAS5614LA