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manual abstract
2 APPLICATIONS · Television sets · Home-sound sets · Multimedia systems · All mains fed audio systems. 4 QUICK REFERENCE DATA 3 GENERAL DESCRIPTION The TDA8928J is a switching power stage for a high efficiency class-D audio power amplifier system. With this power stage a compact 2 . 10 W self oscillating digital amplifier system can be built, operating with high efficiency and very low dissipation. No heatsink is required. The system operates over a wide supply voltage range from ±7.5 V up to ±30 V and consumes a very low quiescent current. SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT General VP supply voltage ±7.5 ±12.5 ±30 V Iq(tot) total quiescent current no load connected; VP = ±12.5 V - 25 45 mA h efficiency Po = 10 W; RL =8 W; VP = ±12.5 V - 90 - % Stereo single-ended configuration Po output power RL =8 W; THD = 10 %; VP = ±12.5 V 9 10 - W RL =16 W; THD = 10 %; VP = ±12.5 V - 5 - W ORDERING INFORMATION TYPE PACKAGE NUMBER NAME DESCRIPTION VERSION TDA8928J DBS17P plastic DIL-bent-SIL power package; 17 leads (lead length 7.7 mm) SOT243-3 TDA8928ST RDBS17P plastic rectangular DIL-bent-SIL power package; 17 leads (row spacing 2.54 mm) SOT577-2 2004 May 05 3 Philips Semiconductors Preliminary specification Philips Semiconductors Preliminary specification TDA8928J audio amplifier 6 BLOCK DIAGRAM MGX377 CONTROL AND HANDSHAKE DRIVER HIGH TDA8928J TEMPERATURE SENSOR AND CURRENT PROTECTION DRIVER LOW temp current 4 7 VSS1 VSS1 VSS2 VDD2 6 1 2 9 8 10 VDD2 VDD1 13 5 CONTROL AND HANDSHAKE DRIVER HIGH DRIVER LOW 14 11 12 17 16 3 15 EN1 DIAG REL1 SW1 SW2 REL2 POWERUP EN2 BOOT1 OUT1 STAB OUT2 BOOT2 Fig.1 Block diagram. 2004 May 05 4 Philips Semiconductors Preliminary specification Philips Semiconductors Preliminary specification TDA8928J audio amplifier 7 PINNING SYMBOL PIN DESCRIPTION SW1 1 digital switch input; channel 1 REL1 2 digital control output; channel 1 DIAG 3 digital open-drain output for overtemperature and overcurrent report EN1 4 digital enable input; channel 1 VDD1 5 positive power supply; channel 1 BOOT1 6 bootstrap capacitor; channel 1 OUT1 7 PWM output; channel 1 VSS1 8 negative power supply; channel 1 STAB 9 decoupling internal stabilizer for logic supply VSS2 10 negative power supply; channel 2 OUT2 11 PWM output; channel 2 BOOT2 12 bootstrap capacitor; channel 2 VDD2 13 positive power supply; channel 2 EN2 14 digital enable input; channel 2 POWERUP 15 enable input for switching on internal reference sources REL2 16 digital control output; channel 2 SW2 17 digital switch input; channel 2 SW1 REL1 DIAG EN1 VDD1 BOOT1 OUT1 VSS1 STAB VSS2 OUT2 BOOT2 VDD2 EN2 POWERUP REL2 SW2 TDA8928J 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 MGX378 Fig.2 Pin configuration. 2004 May 05 5 Philips Semiconductors Preliminary specification Power stage 2 x 10 or 1 x 20 W class-D TDA8928J audio amplifier 8 FUNCTIONAL DESCRIPTION The TDA8928J is a two-channel audio power amplifier system using class-D technology. The power stage TDA8928J is used for driving the loudspeaker load. It performs a level shift from the low-power digital PWM signal, at logic levels, to a high-power PWM signal that switches between the main supply lines. A 2nd-order low-pass filter converts the PWM signal into an analog audio signal across the loudspeaker. 8.1 Power stage The power stage contains high-power DMOS switches, drivers, timing and handshaking between the power switches and some control logic (see Fig.1). The following functions are available: • Switch (pins SW1 and SW2): digital inputs; switching from VSS to VSS + 12 V and driving the power DMOS switches • Release (pins REL1 and REL2): digital outputs; switching from VSS to VSS + 12 V; follow pin SW1 and SW2 with a small delay. Note: for self oscillating applications this pin is not used • Power-up (pin POWERUP): must be connected to a continuous supply voltage of at least VSS + 5 V with respect to VSS • Enable (pins EN1 and EN2): digital inputs; at a level of VSS the power DMOS switches are open and the PWM outputs are floating; at a level of VSS + 12 V the power stage is operational • Diagnostics (pin DIAG): digital open-drain output; pulled down to VSS if the maximum temperature or maximum current is exceeded. 8.2 Protection Temperature and short-circuit protection sensors are included in the TDA8928J. The diagnostic output is pulled down to VSS in the event that the maximum current or maximum temperature is exceeded. The system shuts itself down when pin DIAG is connected to pins EN1 and EN2. 8.2.1 MAXIMUM TEMPERATURE Pin DIAG becomes LOW if the junction temperature (Tj) exceeds 150 °C. Pin DIAG becomes HIGH again if Tj is dropped to approximately 130 °C, so there is a hysteresis of approximately 20 °C. 8.2.2 MAXIMUM CURRENT When the loudspeaker terminals are short-circuited this will be detected by the current protection. Pin DIAG becomes LOW if the output current exceeds the maximum output current of 2 A. Pin DIAG becomes HIGH again if the output current drops below 2 A. The outp...