 |
Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
|
Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
TDA8929 Datasheet(PDF) 9 Page - NXP Semiconductors |
|
||||||||||||||||||||||||||||||
TDA8929 Datasheet(HTML) 9 Page - NXP Semiconductors |
|
|
9 / 36 page  2001 Dec 11 9 Philips Semiconductors Preliminary specification Controller class-D audio amplifier TDA8929T 8.2 Pulse width modulation frequency The output signal of the power stage is a PWM signal with a carrier frequency of approximately 300 kHz. Using a second-order LC demodulation filter in the application results in an analog audio signal across the loudspeaker. This switching frequency is fixed by an external resistor ROSC connected between pin OSC and VSS. With the resistor value given in the application diagram, the carrier frequency is typical 317 kHz. The carrier frequency can be calculated using: [Hz] If two or more class-D systems are used in the same audio application, it is advised to have all devices working at the same switching frequency. This can be realized by connecting all OSC pins together and feed them from an external oscillator. Using an external oscillator it is necessary to force pin OSC to a DC-level above SGND for switching from the internal to an external oscillator. In this case the internal oscillator is disabled and the PWM will switch on the external frequency. The frequency range of the external oscillator must be in the range as specified in the switching characteristics. Application in a practical circuit: • Internal oscillator: ROSC connected between pin OSC and VSS • External oscillator: connect oscillator signal between pin OSC and pin SGND; delete ROSC. 8.3 Protections The controller is provided with two diagnostic inputs. One or both pins can be connected to the diagnostic output of one or more power stages. 8.3.1 DIAGNOSTIC TEMPERATURE A LOW level on pin DIAGTMP will immediately force both pins EN1 and EN2 to a LOW level. The power stage shuts down and the temperature is expected to drop. If pin DIAGTMP goes HIGH, pins EN1 and EN2 will immediately go HIGH and normal operation will be maintained. Temperature hysteresis, a delay before enabling the system again, is arranged in the power stage. Internally there is a pull-up resistance to 5 V at the diagnostic input of the controller. Because the diagnostic output of the power stage is an open-drain output, diagnostic lines can be connected together (wired-OR). It should be noted that the TDA8929T itself has no temperature protection. 8.3.2 DIAGNOSTIC CURRENT This input is intended to protect against short-circuits across the loudspeaker load. In the event that the current limit in the power stage is exceeded, pin DIAGCUR must be pulled to a LOW level. A LOW level on the diagnostic current input will immediately force the output pins EN1 and EN2 to a LOW level. The power stage will shut down within less than 1 µs and the high current is switched off. In this state the dissipation is very low. Every 220 ms the controller will attempt to restart the system. If there is still a short-circuit across the loudspeaker load, the system is switched off again as soon as the maximum current is exceeded. The average dissipation will be low because of this low duty factor. The actual current limiting value is set by the power stage. Depending on the type of power stage which is used, several values are possible: • TDA8926TH: limit value can be externally adjusted with a resistor; maximum is 5 A • TDA8927TH: limit value can be externally adjusted with a resistor; maximum is 7.5 A • TDA8926J and TDA8926ST: limit value is fixed at 5 A • TDA8927J and TDA8927ST: limit value is fixed at 7.5 A. f osc 910 9 × R OSC ------------------- = |
Número de pieza similar - TDA8929 |
|
Descripción similar - TDA8929 |
|
|
Enlace URL |
| Política de Privacidad |
| ALLDATASHEET.ES |
| ¿ALLDATASHEET es útil para Ud.? [ DONATE ] |
Todo acerca de Alldatasheet | Publicidad | Contáctenos | Política de Privacidad | Intercambio de Enlaces | Lista de Fabricantes All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Spanish ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
