CS35L32 datasheet(17/51 Pages) CIRRUS

17 / 51 page

DS963F5

CS35L32

4.4 Low-Battery Management

4.3.2

Class G Operation with LEDs On

If LEDs are active, the speaker amplifier supply in one of the following supply modes, as specified by VBOOST_MNG (see

Section 4.10.3 and Section 7.12 for details):

• Class G operation defaults to the higher supply setting: that requested by the LEDs or that requested by Class G.

The latter takes into account both thresholds VIN1THOF and VIN1THON, as described in Section 4.3.1.

• Class G disabled and the speaker amplifier supply is set as requested by the LEDs. Thresholds are ignored.

• Class G disabled where the boost converter is in Bypass Mode (VBST = VP). Thresholds are ignored.

• Class G disabled where the boost converter is in Boost Mode and VBST = 5 V. Thresholds are ignored.

4.3.3

Error Conditions

Table 4-2 provides links to error status and mask bits for the Class D audio amplifier errors.

The CS35L32 monitors the OUT± terminals in real time to determine whether the output voltage signal correlates to the

PWM data stream driving the gate drivers internal to the device. If it is not, the CS35L32 interprets the discrepancy as a

short on the outputs, which may have been caused by a short to ground, across the speaker, or to the VBST rail.

If this error occurs, the AMP_SHORT status bit is set, and, if M_AMP_SHORT = 0, INT is asserted. As a result, the device

enters Speaker-Safe Mode, which is described in Section 4.3.4.

The CS35L32 also enters Speaker-Safe Mode if its temperature exceeds the overtemperature shutdown threshold

specified in Table 3-3. The OTE status bit is set; if M_OTE = 0, INT is asserted.

The amplifier shuts down automatically due to battery (VP) undervoltage, as described in Section 4.5. The amplifier

restarts automatically upon voltage recovery, with default gain.

The audio amplifier outputs are clamped to ground if MCLK stops, as described in Section 4.13.3.

4.3.4

Speaker-Safe Mode

Speaker-Safe Mode is entered according to the AMP_SHORT and OTE interrupt status bits as follows:

• In the event of an AMP_SHORT, the CS35L32 mutes the amplifier output to Hi-Z to protect the speaker while the

boost converter is allowed to operate normally.

• In the event of an OTE, the CS35L32 mutes the amplifier output to Hi-Z to protect the speaker and sets the boost

converter in Bypass Mode (VBST = VP). Normal behavior resumes when the error condition ceases and OTE_RLS

is sequenced as described in Section 4.7.1.

• If Speaker-Safe Mode is entered as a result of an AMP_SHORT error, normal behavior resumes when the short

condition ceases and the AMP_SHORT_RLS bit is sequenced as described in Section 7.15.

4.4 Low-Battery Management

Under heavy current loading, such as a high current LED flash event, the battery voltage drops. LOWBAT_TH (see p. 37)

allows the user to select a voltage threshold, below which flash current is reduced from the LED_FLCUR setting (see p. 43)

to the LED_FLINHCUR setting (see p. 44). Upon voltage recovery above LOWBAT_RECOV (see p. 37), the flash current

setting reverts to normal. The user should select a recovery threshold higher than the low-battery threshold.

Low-Battery Mode is entered only if a battery voltage falls below the programmed LOWBAT_TH during a flash event. This

condition is reported by the setting LOWBAT (see p. 42), which can be masked with M_LOWBAT (see p. 41).

INT is deasserted after the interrupt registers are cleared by being read, provided the condition no longer exists.

Table 4-2. Class D Audio Amplifier Error Status and Mask Bits

Error

Cross-Reference to Description

Amplifier short/Amplifier short mask

Amplifier short release

Overtemperature error/Overtemperature error mask

Overtemperature error release

AMP_SHORT p. 41, M_AMP_SHORT p. 40, also see Section 4.3.3

AMP_SHORT_RLS p. 39

OTE p. 41, M_OTE p. 40, also see Section 4.3.3

OTE_RLS p. 40

CS35L32 датащи(PDF) 17 Page - Cirrus Logic

CS35L32 датащи(HTML) 17 Page - Cirrus Logic

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

датащи скачать

ссылки URL