TDA16888 查看數據表（PDF） - Infineon Technologies

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TDA16888

High Performance Power Combi Controller

Infineon Technologies 

TDA 16888

2

Functional Description

Power Supply

The TDA 16888 is protected against overvoltages typically above 17.5 V by an internal

Zener diode Z3 at pin 9 (VCC) and against electrostatic discharging at any pin by special

ESD circuitry.

By means of its power management the TDA 16888 will switch from internal stand-by,

which is characterized by negligible current consumption, to operation mode as soon as

a supply voltage threshold of 14 V at pin 9 (VCC) is exceeded. To avoid uncontrolled

ringing at switch-over an undervoltage lockout is implemented, which will cause the

power management to switch from operation mode to internal stand-by as soon as the

supply voltage falls below a threshold of 11 V. Therefore, even if the supply voltage will

fall below 14 V, operation mode will be maintained as long as the supply voltage is well

above 11 V.

As soon as the supply voltage has stabilized, which is determined by the TDA 16888’s

power management and its soft-start feature at pin 13 (PWM SS), the PWM section will

be enabled by means of its internal bias control.

Protection Circuitry

Both PFC and PWM section are equipped with a fast overvoltage protection (C6)

sensing at pin 19 (PFC VS), which when being activated will immediately shut down both

gate drives. In addition to improve the PFC section’s load regulation it uses a fast but soft

overvoltage protection (OTA2) prior to the one described above, which when being

activated will cause a well controlled throttling of the multiplier output QM.

In case an undervoltage of the PFC output voltage is detected at pin 19 (PFC VS) by

comparator C4 the gate drive of the PWM section will be shut down in order to reduce

the load current and to increase the PFC output voltage. This undervoltage shutdown

has to be prior to the undervoltage lockout of the internal power management and

therefore has to be bound to a threshold voltage at pin 9 (VCC) well above 11 V.

In order to prevent the external circuitry from destruction the PFC output PFC OUT

(pin 8) will immediately be switched off by comparator C2, if the voltage at pin 19

(PFC VS) drops to ground caused by a broken wire. In a similar way measures are taken

to handle a broken wire at any other pin in order to ensure a safe operation of the IC and

its adjoining circuitry.

If necessary both outputs, PFC OUT (pin 8) and PWM OUT (pin 10), can be shutdown

on external request. This is accomplished by shorting the external reference voltage at

pin 2 (VREF) to ground. To protect the external reference, it is equipped with a foldback

characteristic, which will cut down the output current when VREF (pin 2) is shorted (see

Figure 4).

Data Sheet

6

2000-02-28

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