Infineon TDA16847G, TDA16847, TDA16846G, TDA16846 Datasheet

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ICs for Consumer Electronics

Controller for Switch Mode Power Supplies Supporting Low Power Standby and Power Factor Correction

TDA 16846/TDA 16847

Data Sheet 2000-01-14

TDA 16846/TDA 16847
Revision History:		Current Version: 2000-01-14

Previous Version: 1999-07-05

Page	Page	Subjects (major changes since last revision)
(in previous	(in current
Version)	Version)

3	3, 28	P-DSO package added

Edition 01.00

Published by Infineon Technologies AG i. Gr., St.-Martin-Strasse 53

D-81541 München

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Warnings

Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Infineon Technologies Office.

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Controller for Switch Mode Power Supplies Supporting Low Power Standby and Power Factor Correction

Preliminary Data

TDA 16846 TDA 16847

Bipolar IC

1	Overview
1.1	Features
• Line Current Consumption with PFC		P-DIP-14-3
• Low Power Consumption		P-DIP-14-3
• Low Power Consumption
• Stable and Adjustable Standby Frequency
• Very Low Start-up Current
• Soft-Start for Quiet Start-up

•Free usable Fault Comparators

•Synchronization and Fixed Frequency Facility

• Overand Undervoltage Lockout	P-DSO-14-3

•Switch Off at Mains Undervoltage

•Temporary high power circuit (only TDA 16847)

•Mains Voltage Dependent Fold Back Point Correction

•Continuous Frequency Reduction with Decreasing Load

•Adjustable and Voltage Dependent Ringing Suppression Time

Type	Ordering Code	Package

TDA 16846	Q67000-A9377	P-DIP-14-3

TDA 16847	Q67000-A9378	P-DIP-14-3

TDA 16846G	Q67006-A9430	P-DSO-14-3

TDA 16847G	Q67006-A9412	P-DSO-14-3

1.2Description

The TDA 16846 is optimized to control free running or fixed frequency flyback converters with or without Power Factor Correction (Current Pump). To provide low power consumption at light loads, this device reduces the switching frequency continuously with load, towards an adjustable minimum (e. g. 20 kHz in standby mode). Additionally, the start up current is very low. To avoid switching stresses of the power devices, the power transistor is always switched on at minimum voltage. A special circuit is implemented to avoid jitter. The device has several protection functions: VCC overand undervoltage, mains undervoltage, current limiting and 2 free usable fault comparators. Regulation can be done by using the internal error amplifier or an opto coupler feedback (additional input). The output driver is ideally suited for driving a power MOSFET, but it can also be used for a bipolar transistor. Fixed frequency and synchronized operation are also possible.

Data Sheet

2000-01-14

TDA 16846

TDA 16847

The TDA 16846 is suited for TV-, VCRsets and SAT receivers. It also can be good used in PC monitors.

The TDA 16847 is identical with TDA 16846 but has an additional power measurement output (pin 8) which can be used for a Temporary High Power Circuit.

OTC	1		VCC
		14
PCS	2	13	OUT

RZI	3	12	GND

SRC	4	11	PVC

OCI	5	10	FC1

FC2	6	9	REF

SYN	7	8	N.C./PMO

AEP02647

Figure 1 Pin Configuration (top view)

1.3Pin Definitions and Functions

Pin	Symbol	Function

1	OTC	Off Time Circuit

2	PCS	Primary Current Simulation

3	RZI	Regulation and Zero Crossing Input

4	SRC	Soft-Start and Regulation Capacitor

5	OCI	Opto Coupler Input

6	FC2	Fault Comparator 2

7	SYN	Synchronization Input

8	N.C./PMO	Not Connected (TDA 16846)/PMO (TDA 16847)

9	REF	Reference Voltage and Current

10	FC1	Fault Comparator 1

11	PVC	Primary Voltage Check

12	GND	Ground

13	OUT	Output

14	VCC	Supply Voltage

Data Sheet		4	2000-01-14

TDA 16846

TDA 16847

1.4Short Description of the Pin Functions

Pin	Function
1	A parallel RC-circuit between this pin and ground determines the ringing
	suppression time and the standby-frequency.

2A capacitor between this pin and ground and a resistor between this pin and the positive terminal of the primary elcap quantifies the max. possible output power of the SMPS.

3This is the input of the error amplifier and the zero crossing input. The output of a voltage divider between the control winding and ground is connected to this input. If the pulses at pin 3 exceed a 5 V threshold, the control voltage at pin 4 is lowered.

4This is the pin for the control voltage. A capacitor has to be connected between this pin and ground. The value of this capacitor determines the duration of the softstart and the speed of the control.

5If an opto coupler for the control is used, it’s output has to be connected between this pin and ground. The voltage divider at pin 3 has then to be changed, so that the pulses at pin 3 are below 5 V.

6Fault comparator 2: If a voltage > 1.2 V is applied to this pin, the SMPS stops.

7If fixed frequency mode is wanted, a parallel RC circuit has to be connected between this pin and ground. The RC-value determines the frequency. If synchronized mode is wanted, sync pulses have to be fed into this pin.

8Not connected (TDA 16846). / This is the power measurement output of the Temporary High Power Circuit. A capacitor and a RC-circuit has to be connected between this pin and ground (TDA 16847).

9	Output for reference voltage (5 V). With a resistor between this pin and ground
	the fault comparator 2 (pin 6) is enabled.

10	Fault comparator 1: If a voltage > 1 V is applied to this pin, the SMPS stops.

11This is the input of the primary voltage check. The voltage at the anode of the primary elcap has to be fed to this pin via a voltage divider. If the voltage of this pin falls below 1 V, the SMPS is switched off. A second function of this pin is the primary voltage dependent fold back point correction (only active in free running mode).

12	Common ground.
13	Output signal. This pin has to be connected across a serial resistor with the
	gate of the power transistor.

14Connection for supply voltage and startup capacitor. After startup the supply voltage is produced by the control winding of the transformer and rectified by an external diode.

Data Sheet

2000-01-14

TDA 16846

TDA 16847

1.5Block Diagrams

PVC

SYN

Fold Back Point Correction

R6 x 1/3

Primary

KSY

PVA

Voltage

5 V

Check

30 kΩ

1 V

1.5 V

75 kΩ

15 kΩ

Control Voltage

Off Time

3.5 V

VCC

Limit

Comparator

2 V

ED2

OTC

CS1

REF

RSTC/RSTF

N.C.

3.5 V

5 V

Error

FC2

Amplifier

Error-

Flipflop

FC2

1.2 V

RZI

Buffer for

Control Voltage

SRC

OCI

On Time

Output

Flipflop

20 kΩ

Comparator

Driver

5 V

OUT

PCS

ED1

Zero Crossing

1.5 V

Signal

< 25 mV

Startup

Supply

Diode

Overvoltage

FC1

Voltage

Comparator

1 V

VCC

GND

16 V

15/8 V

The input with the lower voltage becomes operative

FC1

AEB02648

Figure 2	TDA 16846
Data Sheet	6	2000-01-14

TDA 16846

TDA 16847

PVC

SYN

Fold Back Point Correction

R6 x 1/3

Primary

KSY

PVA

Voltage

Check

5 V

30 kΩ

1 V

1.5 V

75 kΩ

15 kΩ

Control Voltage

VCC

Off Time

3.5 V

Limit

Comparator

2 V

REF

OTC

ED2

PMO

CS1

RSTC/RSTF

3.5 V

5 V

Error

FC2

Amplifier

Error-

Flipflop

FC2

1.2 V

RZI

Buffer for

Control Voltage1)

SRC

OCI

On Time

Output

Flipflop

20 kΩ

Comparator

Driver

5 V

OUT

PCS

Discharge Time

ED1

Zero

Flipflop

1.5 V

Crossing

Signal

< 25 mV

Startup

FC1

Diode

Overvoltage

Supply Voltage

1 V

Comparator

VCC

GND

16 V

15/8 V

The input with the lower voltage becomes operative

FC1

AEB02737

Figure 3

TDA 16847

Data Sheet

2000-01-14

TDA 16846

TDA 16847

2 Functional Description

Start Up Behaviour (Pin 14)

When power is applied to the chip and the voltage V14 at Pin 14 (VCC) is less than the upper threshold (VON) of the Supply Voltage Comparator (SVC), input current I14 will be less than 100 A. The chip is not active and driver output (Pin 13) and control output (Pin 4) will be actively held low. When V14 exceeds the upper SVC threshold (VON) the chip starts working and I14 increases. When V14 falls below the lower SVC threshold (VOFF) the chip starts again at his initial condition. Figure 4 shows the start-up circuit and Figure 5 shows the voltage V14 during start up. Charging of C14 is done by resistor R2 of the “Primary Current Simulation” (see later) and the internal diode D1, so no additional start up resistor is needed. The capacitor C14 delivers the supply current until the auxiliary winding of the transformer supplies the chip with current through the external diode D14.

It is recommended to switch a small RF snubber capacitor of e.g. 100 nF parallel to the electrolytic capacitor at pin 14 as shown in the application circuits in Figures 15, 16, and 17.

		D14
	C14	VCC
	C14	14
		14
		SVC
		TR
	C2	D1
	PCS	2

R2	TDA 16846
	VOut

AES02649

Figure 4 Startup Circuit

Data Sheet

2000-01-14

TDA 16846

TDA 16847

	Vmax
V14	V
	On
	VOff
	Startup	Operation
		t
		AED02650

Figure 5 Startup Voltage Diagram

Primary Current Simulation PCS (Pin 2) / Current Limiting

A voltage proportional to the current of the power transistor is generated at Pin 2 by the RC-combination R2, C2 (Figure 4). The voltage at Pin 2 is forced to 1.5 V when the power transistor is switched off and during its switch on time C2 is charged by R2 from the rectified mains. The relation of V2 and the current in the power transistor (Iprimary) is

V2	= 1,5 V + L---pr----imary---------×---	-I-pri----mary------
	R2 ×	C2

Lprimary: Primary inductance of the transformer

The voltage V2 is applied to one input of the On Time Comparator ONTC (see Figure 2). The other input is the control voltage. If V2 exceeds the control voltage, the driver switches off (current limiting). The maximum value of the control voltage is the internal reference voltage 5 V, so the maximum current in the power transistor (IMprimary) is

IMprimary	3,5 V × R2 × C2
IMprimary	= --------------------------------------
	Lprimary

The control voltage can be reduced by either the Error Amplifier EA (current mode regulation), or by an opto coupler at Pin 5 (regulation with opto coupler isolation) or by the voltage V11 at Pin 11 (Fold Back Point Correction).

Data Sheet

2000-01-14

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