Siemens TDA4817G, TDA4817 Datasheet

Power Factor Controller

TDA 4817

IC for High Power Factor and
Active Harmonic Filtering

Advance Information Bipolar IC

Features

● IC for sinusoidal line-current consumption

● Power factor approaching 1

● Controls boost converter as an active harmonics filter

● Direct drive of SIPMOS transistor

● Zero crossing detector for discontinuous operation mode

with variable frequency

● 110/220 V AC operation without switchover

● Standby current consumption of 0.5 mA

P-DIP-8-1

P-DSO-8-1

Type Ordering Code Package

▼

TDA 4817 Q67000-A8298 P-DIP-8-1

▼

TDA 4817 G Q67000-A8299 P-DSO-8-1 (SMD)
▼ = New type

The TDA 4817 contains all functions for designing electronic ballasts and switched-mode power
supplies with sinusoidal line current consumption and a power factor approaching 1.

The TDA 4817 controls a boost converter as an active harmonic filter in a discontinuous (triangular
shaped current) mode with variable frequency.

A typical application is in electronic ballasts, especially when a large number of such lamps are
concentrated on one line supply point.

The output voltage of this filter is regulated with high efficiency. Therefore the device can be easily
operated on different line voltages (110/220 V

) without any switchover.

AC

The TDA 4817 is an 8-pin-economy-version of the TDA 4814 A without reference voltage output
and start/stop monitoring circuit.

Semiconductor Group 1 05.95

TDA 4817 TDA 4817 G

TDA 4817

Pin Configurations

(top view)

Pin Definitions and Functions
Pin Symbol Function

1 GND Ground
2 QSIP Driver output
3

V

S

Supply voltage
4 C – Comparator input
5 IM1 Multiplier input
6 OP – Input
7 QOP/IM2 Operational-amplifier output QOP and multiplier input M2
8 I Detector Detector input

Semiconductor Group 2

TDA 4817

Block Diagram

Semiconductor Group 3

TDA 4817

Circuit Description

This device has a conditioning circuit for the internal power supply. It allows standby operation with
very low current consumption (less than 0.5 mA), a hysteresis between enable and switch-off levels
and an internal voltage stabilization. An integrated Z-diode limits the voltage onVS, when impressed
current is fed.

The output driver (Q SIP) is controlled by detector input and current comparator.
The detector input (I DET) which is highly resistive in the operating state reacts on hysteresis-

determined voltage levels. To keep down the amount of circuitry required, clamping diodes are
provided which allow control by a current source.

The operating state of the boost converter choke is sensed via the detector input. H-level means
that the choke discharges and the output driver is inhibited. H-level sets a flip-flop, which stores the
switch-off instruction of the current comparator to reduce susceptibility to interference. As soon as
demagnetization is finished the choke voltage reverses and the detector input is set to L-level, thus
enabling the output driver. This ensures that the choke is always currentless when the SIPMOS
transistor switches on and that no current gaps appear.

The nominal voltage of the multiplier output is compared to the voltage derived from the actual line
current (– I COMP), thus setting the switch-off threshold of the comparator. The current comparator
blocks the output driver when the nominal peak value of the choke current given by the multiplier
output is reached.

This state is maintained in the flip-flop until H-level appears at detector input which takes over the
hold function and resets the flip-flop.

Operating states might occur without any useful detector signal. This is the case with magnetic
saturation of the choke and when the input voltage approaches or exceeds the output voltage as,
for example, during switch-on. The driver remains inhibited for the flip-flop due to the absent set
signal.

The trigger signal can be derived from the subsequent lamp generator or a SMPS control device.
The trigger signal level should be so low that with standard operation the signal from the detector
winding dominates. The multiplier delivers the preset nominal value for the current comparator by
multiplying the input voltage (IM1), which determines the nominal waveform and the output voltage
of the control amplifier.

The control amplifier stabilizes the output dc voltage of the active harmonic filter in the event of load
and input voltage changes. The control amplifier compares the actual output voltage to a
reference voltage which is provided in the IC and stable with temperature.

Output Driver

The output driver is intended to drive a SIPMOS transistor directly.
It is designed as a push-pull stage.
Both the capacitive input impedance and keeping the gate level at zero potential in standby

operation by an internal 10-kΩ-resistor are taken into account. Possible effects on the output driver
by line inductances or capacitive couplings via SIPMOS transistor Miller capacitance are limited by
diodes connected to ground and supply voltage.

Semiconductor Group 4