CS43L36 datasheet(24/89 Pages) CIRRUS

24 / 89 page

DS1081F3

CS43L36

4.3 Class H Amplifier

The CS43L36 HP output amplifiers use a Cirrus Logic four-mode Class H technology, which maximizes operating

efficiency of the typical Class AB amplifier while maintaining high performance. In a Class H amplifier design, the rail

voltages supplied to the amplifier vary with the needs of the music passage being amplified. This conserves energy during

low-power passages and when the program material is played back at low volume.

The internal charge pump, which creates the rail voltages for the HP amplifiers, is the central component of the four-mode

Class H technology. The charge pump receives its input voltage from the voltage present on either the VCP or VP pin.

From this voltage, the charge pump generates the differential rail voltages supplied to the amplifier output stages. The

charge pump can supply four sets of differential rail voltages: ±2.5, ±VCP, ±VCP/2, and ±VCP/3.

Table 4-1 shows the nominal signal- and volume-level ranges if the amplifier is set to the adapt-to-signal mode explained

in Section 4.3.1. In addition to adapting to the input signal, the Class H control is capable of monitoring the internal

headphone amplifier supply to allow more efficient, load-dependent, automatic Smart Class H Mode selection. In fixed

modes, if the signal level exceeds the maximum value of the indicated range, clipping can occur.

4.3.1

Power Control Options

This section describes the supported types of operation: standard Class AB and adapt to signal. The set of rail voltages

supplied to the amplifier output stages depends on the ADPTPWR setting, as described in Section 7.10.1.

4.3.1.1 Standard Class AB Operation (ADPTPWR = 001, 010, 011, or 100)

If ADPTPWR is set to 001, 010, 011, or 100, the rail voltages supplied to the amplifiers are held to ±2.5, ±VCP, ±VCP/2,

or ±VCP/3, respectively. For these settings, the rail voltages supplied to the output stages are held constant, regardless

of the signal level. In these settings, the CS43L36 amplifiers operate in a traditional Class AB configuration.

4.3.1.2 Adapt-to-Output Signal (ADPTPWR = 111)

If ADPTPWR = 111, the rail voltage sent to the amplifiers is based only on whether the signal sent to the amplifiers would

cause the amplifiers to clip when operating on the lower set of rail voltages at certain threshold values.

• If clipping can occur, the control logic instructs the charge pump to provide the next higher set of rail voltages.

• If clipping could not occur, the control logic instructs the charge pump to provide the lower set of rail voltages,

eliminating the need to advise the CS43L36 of volume settings external to the device.

Table 4-1. Class H Supply Modes

Load

Mode

Class-H Supply Voltage

Signal-Level Range 1,2,3,4

1.In Adapt-to-Signal Mode, volume level ranges are approximations but are within –0.5 dB from the values shown.

2.Relative to digital full scale with FULL_SCALE_VOL set to 0 dB.

3.In fixed modes, clipping occurs if the signal level exceeds the maximum of this range due to setting the amplifier’s supply too low.

4.To optimize efficiency, smart Class H thresholds automatically vary based on load conditions.

Resistance

Capacitance



1 nF

±2.5 V

≥ –8 dB

± VCP

–9 to –14 dB

± VCP/2

–15 to –20 dB

± VCP/3

≤ –21 dB

10 nF

±2.5 V

≥ –9 dB

± VCP

–10 to –14 dB

± VCP/2

–15 to –19 dB

± VCP/3

≤ –20 dB



1 or 10 nF

±2.5 V

≥ –4 dB

± VCP

–5 to –11 dB

± VCP/2

–12 to –16 dB

± VCP/3

≤ –17 dB

3 k



1 or 10 nF

±2.5 V

≥ –1 dB

± VCP

–2 to –8 dB

± VCP/2

–9 to –13 dB

± VCP/3

≤ –14 dB

CS43L36 датащи(PDF) 24 Page - Cirrus Logic

CS43L36 датащи(HTML) 24 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 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89

датащи скачать

ссылки URL