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UCC2750

UCC3750

DESCRIPTION

The UCC3750 Source Ringer Controller provides a complete control and

drive solution for a four quadrant flyback-based ring generator circuit. The

IC controls a primary side switch, which is modulated when power transfer

is taking place from input to output. It also controls two secondary

switches which act as synchronous rectifier switches during positive

power flow. These switches are pulse-width-modulated when the power is

being delivered back to the source.

The UCC3750 has an onboard sine wave reference with programmable

frequencies of 20Hz, 25Hz and 50Hz. The reference is derived from a

high-frequency (32kHz) crystal connected externally. Two fre

quency-select pins control an internal divider to give a sinusoidal output at

20Hz, 25Hz or 50Hz. The ring generator can also be used at other fre

quencies by supplying externally generated sine-waves to the chip or by

clocking the crystal input at a fixed multiple of the desired frequency.

Other features included in the UCC3750 are programmable DC current

limit (with buffer amplifier), a charge-pump circuit for gate drive voltage, in

ternal 3V and 7.5V references, a triangular clock oscillator and a buffer

amplifier for adding programmable DC offset to the output voltage. The

UCC3750 also provides an uncommitted amplifier (AMP) for other signal

processing requirements.

Source Ringer Controller

26 27 25

OUT2

NEG2

VS 2

VDD

VS 1

VC P

OUT1

NEG1

REFENBLGD3GD2

SINFLT

OUTDC

NEGDC

RGOOD

GD1

AMP O UT

XTAL1

XTAL2

AMP IN

FS 0

FS 1

48V

UCC3750

9 8 3

SINREF SWRLY GND

C17

0.047µF

OUT

–48V

OUT

TYPICAL APPLICATION

FEATURES

•

Provides Control for Flyback Based

Four Quadrant Amplifier Topology

•

Onboard Sine Wave Reference with

Low THD

•

Selectable Ringing Frequency for

Different Phone Systems (20Hz,

25Hz and 50Hz)

•

Programmable Output Amplitude and

DC Offset

•

DC Current Limiting for Short Circuit

Protection

•

Secondary Side Voltage Mode

Control

•

Operates from a Single 5V Supply

SLUS172C - DECEMBER 1999 - REVISED AUGUST 2005

UDG-99073

application

INFO

available

Summary of content (18 pages)

PAGE 1
application INFO available UCC2750 UCC3750 Source Ringer Controller FEATURES DESCRIPTION • Provides Control for Flyback Based Four Quadrant Amplifier Topology The UCC3750 Source Ringer Controller provides a complete control and drive solution for a four quadrant flyback-based ring generator circuit. The IC controls a primary side switch, which is modulated when power transfer is taking place from input to output.
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UCC2750 UCC3750 CONNECTION DIAGRAM ABSOLUTE MAXIMUM RATINGS Input Supply Voltage VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5V Maximum Forced Voltage VCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V to 13.2V VS1, VS2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V to 5V OUT1, OUT2, AMPOUT, OUTDC Maximum Forced Voltage . . . . . . . . . . . . . . . . –0.3V to 7.5V Maximum Forced Current . . . . . . . . . . . . . .
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UCC2750 UCC3750 ELECTRICAL CHARACTERISTICS:Unless otherwise stated, these specifications apply for TA = 0°C to 70°C for the UCC3750, –40°C to +85°C for the UCC2750, RT = 14k, CT = 470pF, CREF = 0.1µF, FS0 = 0, FS1 = 0, VDD = 5V. TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Oscillator Accuracy 108 128 148 kHz Peak Voltage 4.6 4.75 4.9 V Valley Voltage 2.9 3.05 3.
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UCC2750 UCC3750 PIN DESCRIPTIONS (cont.) GD2: Output driver that controls the p-channel secondary side switch in the flyback converter. The output signal on this pin is PWM during mode 4 (Fig. 2) when the reference signal is negative and power is being returned to the input. This pin functions as a synchronous rectifier output during mode 1 with positive reference signal and positive power transfer. This output is logically inverted to provide the correct polarity drive signal for a p-channel switch.
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UCC2750 UCC3750 DETAILED BLOCK DIAGRAM SWRLY FS0 8 XTAL1 XTAL2 XTAL OSC 21 13 AMPIN 14 SINREF 19 9 SINFLT NEG1 10 12 VCM – AMP + VCM – + 5 VS2 6 VDD 7 15 REF CHARGE PUMP + – REF – + VCM MAG FULLWAVE RECTIFIER SIGN ERROR AMP MODE INTERNAL REFERENCE REF=7.5V VCM = 3.
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RTN VIN C23 C1 C2 0.47µF 100µF 100µF R22 C22 R1 10k R23 Figure 1. Typical application circuit. 6 1 CR9 3 4 Q6 MP S A06 2 5 1 6 Q5 2 Q4 2N5457 3 1 2N7001DICT 3 2 1 C3 0.1µF R20 1 2 C21 T2 R2 R6 10k 3 VDD C5 0.47µF 4 Q3 S3 S2 S4 S1 X1 32kHz R5 30k R9 AMP IN XTAL1 XTAL2 14 22 21 19 25 16 17 OUT1 NEG1 8 9 3 10 18 GND C11 0.22µF CR5 C9 0.47µF VDD C10 2.2µF C16 2.2µF R12 2.7k C18 22µF R14 3.
PAGE 7
UCC2750 UCC3750 APPLICATION INFORMATION (cont.) When the reference signal goes from positive to negative, a transition is made from mode 2 to mode 3. In mode 3, the converter once again acts as a DC-DC flyback converter (with negative output). Similar to mode 1, Q1 is controlled by the PWM output, however, the rectifying path is now through Q3/DR3 as the output polarity is reversed. At the mode boundaries, there could be some distortion which won’t affect the THD too much as it is near zero crossings.
PAGE 8
UCC2750 UCC3750 APPLICATION INFORMATION (cont.) R13  R13 R13   • VCM – VOUT1= 1+ + • REF R26  R14 R26  Sine Reference Generator The IC has a versatile low frequency sinewave reference generator with low harmonic distortion and good frequency accuracy. In its intended mode as shown in Fig. 5, the reference generator will take an input from a 32kHz crystal (connected between XTAL1 and XTAL2) and generate a sine-wave at 20Hz, 25Hz or 50Hz based on the programming of pins FS0 and FS1 (See Table 2).
PAGE 9
UCC2750 UCC3750 APPLICATION INFORMATION (cont.) problem is only manifested for high values of VB (e.g. 48V) and can be alleviated by using a fraction of the required DC offset as the VB input and regaining the offset with resistive ratios. ulation turns on the PWM signal when the ramp signal falls below MAG on the falling slope and turns it off at the end of the clock cycle. This technique enables synchronized turn-on of the rectifier switches immediately after the PWM pulse is turned off.
PAGE 10
UCC2750 UCC3750 APPLICATION INFORMATION (cont.) R S ENS E 11 OUTDC R5 R6 12 NEGDC VCM 4 – DC + TO P WM UDG-96170-1 Figure 8. Current limiting. Figure 9. Charge pump circuits. reset (and to transfer power to the output). Operation in quadrants 3 and 4 is symmetrical to the first two quadrants with Q2 and Q3 interchanged. Note that the output signal for Q2 is logically inverted to allow for driving the p-channel switch.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 11-Apr-2013 (4) Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Top-Side Marking for that device. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided.
PAGE 13
PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device UCC3750DWTR Package Package Pins Type Drawing SOIC DW 28 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 1000 330.0 32.4 Pack Materials-Page 1 11.35 B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 18.67 3.1 16.0 32.
PAGE 14
PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) UCC3750DWTR SOIC DW 28 1000 367.0 367.0 55.
PAGE 15
MECHANICAL DATA MPDI008 – OCTOBER 1994 N (R-PDIP-T**) PLASTIC DUAL-IN-LINE PACKAGE 24 PIN SHOWN A 24 13 0.560 (14,22) 0.520 (13,21) 1 12 0.060 (1,52) TYP 0.200 (5,08) MAX 0.610 (15,49) 0.590 (14,99) 0.020 (0,51) MIN Seating Plane 0.100 (2,54) 0.021 (0,53) 0.015 (0,38) 0.125 (3,18) MIN 0.010 (0,25) M PINS ** 0°– 15° 0.010 (0,25) NOM 24 28 32 40 48 52 A MAX 1.270 (32,26) 1.450 (36,83) 1.650 (41,91) 2.090 (53,09) 2.450 (62,23) 2.650 (67,31) A MIN 1.230 (31,24) 1.410 (35,81) 1.
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