View TDA8385_171930.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
FEATURES * Bandgap reference generator * Slow-start circuitry * Low-loss peak current sensing * Over-voltage protection * Hysteresis controlled stand-by function * Error amplifier with gain setting * Programmable transfer character generator * Protection against open- and short-circuited feedback loop ORDERING INFORMATION EXTENDED TYPE NUMBER TDA8385 PACKAGE PINS 16 PIN POSITION DIL MATERIAL plastic * Over-load current fold back characteristic * LED driver * Demagnetization protection * Programmable determination of switch-on moment of switching transistor for low-switching losses * Feed-forward input * Regulation-indicator output * Programmable minimum on-time of switching transistor * Accurate peak-current setting.
TDA8385
GENERAL DESCRIPTION The TDA8385 is intended to be used in combination with the opto-coupler (CNR50) as a control unit for a self-oscillating power supply.
CODE SOT38WBE
March 1994
2
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
BLOCK DIAGRAMS
VP
handbook, full pagewidth
TDA8385
GND
16
14 latch
current reference setting
3 I ref
REFERENCE BLOCK 2 I ref Vref
STABILIZED SUPPLY 1 Vstab
V P (min) DETECTOR 28
reset
(28, 27, 23) SUPPLY REFERENCES
I
feed forward input
13 V fo V ts
regulation indicator output
1
RIO REGULATION INDICATOR
29
X
7 Vmv
differential amplifier output
11 V diff DIFFERENTIAL AMPLIFIER Vref (2.5 V) V diff
V ts 3
feedback voltage input
9
Vfb
CLAMP
V TCG
50 A
TCG 2.5 V 4
MINIMUM VOLTAGE CLAMP CONTROL PART
6
III
transistor-on setting input
T 4 on(min)
5 Vss + Ton (min) slow start voltage input 7 Vss reset (28) quick discharge 27 19
50 A charge
SLOW START
VII
MCD417
Fig.1 Block diagram; part A (continued in Fig.2; part B).
March 1994
3
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
TDA8385
handbook, full pagewidth
stand-by voltage input
Vsb latch
10 latch
2.5 V 2V
TDA8385
25
OUTPUT STAGE 15
LED
2
LED driver output
2.5 V
STAND-BY
IX
17 LED DRIVER
Vr Vsim 8
PWM
VI
Q (23)
IV
comparator
18
(28) S FF 26 R Q 14
16
demagnetization 13 LED CONTROL
V
demagnetization I sim Vc 0.2 I 12 9 I peak DEM DELAY 12 100 mV 11 115 mV 6 10 SAWTOOTH GENERATOR delay setting 15 I12 12 5 current simulation input peak-current setting input demagnetization input
II
(17) 100 A slow discharge Q 21 FF 23 Q OVER-VOLTAGE PROTECTION S R
(28) 24 115 mV
over voltage 22 2.5 V
8
over-voltage protection
VIII
MCD418
Fig.2 Block diagram; part B (continued from Fig.1; part A).
March 1994
4
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
PINNING SYMBOL RIO LED Iref Ton(min) Ipeak DELAY Vss OVP Vfb Vsb Vdiff Isim Vfo GND DEM VP PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 DESCRIPTION regulation indicator output LED driver output current reference setting transistor-on setting input peak current setting input delay setting slow start voltage input over-voltage protection feedback voltage input stand-by voltage input differential amplifier output current simulation input feed forward input ground (0 V) demagnetization input positive supply voltage cross-referenced in the following description. Supply references (Block I) The TDA8385 is intended to be used on the secondary side of the self-oscillating power supply. It can be supplied either by an auxiliary winding of the transformer or an external supply e.g. 50 Hz transformer. Charging of the capacitor CP (see Fig.16) takes place during transistor on-time (Ton; see Fig.17). During stand-by the IC is supplied by the stand-by voltage Vsb (pin 10). The operating voltage range is from 7.5 to 20 V. The supply current, inclusive drive current for the LED, is less than 20 mA. A bandgap based reference (2.5 V) generates a stabilized voltage Vstab of 3.9 V to supply all internal circuits of the IC except the LED driver. The LED driver is directly supplied by VP. The reference block generates all the reference voltages in the circuit. By means of a resistor connected to pin 3, a reference current (Iref) is defined. 5
handbook, 2 columns
TDA8385
RIO LED I ref Ton(min) I peak DELAY Vss OVP
1 2 3 4 TDA8385 5 6 7 8
MCD402
16 V P 15 DEM 14 GND 13 Vfo 12 I sim 11 Vdiff 10 Vsb 9 V fb
Fig.3 Pinning diagram.
FUNCTIONAL DESCRIPTION The TDA8385 can be divided into 10 functional blocks as shown in Fig.1 and Fig.2. Block for Figs 1 and 2 BLOCK NO. I II III IV V VI VII VIII IX X DESCRIPTION supply references sawtooth generator control part pulse width modulator (PWM) LED control LED driver slow-start circuitry over-voltage protection stand-by circuit regulation-indicator output
This current is reflected several times and is used to obtain IC-independent settings e.g. Ton(min) setting, delay setting, charging and discharging of slow-start capacitor Css on pin 7 (see Fig.16). The power supply is released by the opto-coupler IC at an input voltage level, which is high enough to guarantee correct operation of the TDA8385 e.g. VP = 10 V by sensing the mains voltage VI. As soon as the SOPS switching transistor (T1, see Fig.16) is conductive the capacitor CP is charged. As long as the IC supply voltage is below 7.5 V the LED driver is blocked (see latch output; sub-section 28) in order to guarantee start-up of SOPS. During the initialization phase the quick-discharge-switch (sub-section 27), set input of flip-flop (13) and reset input of flip-flop (23) are also activated. As soon as the voltage of 7.5 V is reached the control functions of the IC are operative. Hysteresis on the initialization level is 2.3 V.
These 10 functional blocks of Fig.1 and Fig.2 contain sub-sections numbered 1 to 28 which are March 1994
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
Sawtooth generator (Block II) CURRENT SIMULATION (SEE FIGS 5 AND 16) The current of the power supply switching transistor is detected on the secondary side by an indirect method of current sensing. Information of the collector current (Ic) is obtained by integrating the voltage of an auxiliary winding of the transformer during transistor on-time (Ton). An external capacitor C on pin 5 is charged during Ton by the current source Isim. The current Isim is the reflection of the current which flows into pin 12. This current is obtained by connecting an external resistor R12 to the auxiliary transformer winding. During transistor on-time this current is related to the input voltage VI. During transistor off time (Toff) the capacitor C is discharged by switch handbook, full pagewidth sw1. This switch is active during the total Toff time. In this way a sawtooth voltage Vc is formed across C. This sawtooth is a measure for the collector current of the switching transistor T1. For the voltage Vc yields: I sim x T on V c = -----------------------C VI nh I sim = p x ----- x ---------n p R12 Where: p = reflection factor; I sim p = -------- = 0.2 I 12 (2) (1) gives:
t
TDA8385
latch initialization
operation 5.2 7.5 V P (V) 20
MCD403
Fig.4 Latch initialization as a function of supply voltage VP.
R12 L np VI Ic nh I 12 12 5
I sim
(1)
T1
sw1 Vc C
(2)
Vc
VI p nh V c = --- x ----- x ---------- x T on C n p R12
(3)
Ton
Toff
MCD404
Fig.5 Determination of the peak current Ic.
March 1994
6
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
For `Ton' yields: V c x C x n p x R12 T on = ---------------------------------------------p x nh x VI For the primary current Ic yields: VI I c = ---- x T on L Substitution (4) into (5): C 1 np I c = --- x -- x ----- x R12 x V c -L p nh (6) (5) (4) DELAY SETTING (PIN 6) The output of sub-section 11 is extended by the delay circuit of sub-section 12. The starting (reference) point of the delay circuit is the falling edge of the output of demagnetizing comparator (11) The delay can be determined externally by capacitor (Cdelay) on pin 6. The switch-on moment of the switching transistor can be determined by capacitor Cdelay. A minimum delay time is required to prevent transistor T1 from switching during demagnetization of the transformer because of oscillations caused by the leakage inductance.
TDA8385
Control part (Block III) The differential amplifier, sub-section 3, compares the feedback voltage (Vfb) with the reference voltage Vref. The output of the differential amplifier is available on pin 11 to allow gain setting. The differential amplifier is internally compensated for 0 dB feedback stability. The feedback input (pin 9) is also used as the input for the TCG (see Fig.6) with which a current foldback characteristic can be obtained as shown in Fig.7.
Equation (6) shows that by limiting the voltage Vc the collector peak current can be limited. The peak current is limited by means of the clamping circuit in the transfer character generator (TCG); see Fig.1 sub-section 4. The clamping level can be externally influenced by means of a resistor on pin 7. The collector peak current can be influenced in several ways: * Resistor R12 on pin 12 * Capacitor C on pin 5 * Capacitor on pin 7 * Transfer ratio nh/np * Inductance L Before comparing the sawtooth voltage Vc with the control voltage Vr in the pulse width modulator, a voltage of 100 mV is added to Vc. In this way it will be possible for Vr to become smaller than Vsim, which is important for a stabilized no-load operation (see Fig.6 area 3). DEMAGNETIZATION INPUT (PIN 15) This input prevents the switching transistor from conducting during demagnetization of the transformer in order to prevent the transformer from going into saturation. The output of comparator (11) is HIGH as soon as the voltage of the transformer winding exceeds 115 mV. March 1994
(3) Vmv V clamp
(4) (2)
(1) (5) Vfb
V Ton(min)
MCD405
(1), (2), (3) = VTCG. (4), (5) = Vdiff.
Fig.6 Reference voltage (Vmv) as a function of feedback voltage (Vfb).
7
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
TDA8385
The voltage VTon(min) determines the minimum on-time of the switching transistor. This voltage can be determined externally with a resistor on pin 4. With this resistor the current foldback characteristic can be influenced (see dotted line in Figs 6 and 7).
VO (5) (4) (3)
The minimum on-time is of importance for the following. * Stand-by operation * Starting-up of power supply
(2)
* Overload and short-circuit conditions. The output of the differential amplifier (Vdiff), the output of the TCG (VTCG) and the voltage Vss + VTon(min) are compared in a minimum voltage clamping circuit (see Fig.1 sub-section 6). The output voltage is equal to the lowest input voltage. Some relevant characteristics of the control part are depicted in Fig.8.
(1) IO
MCD406
(1), (2), (3) = VTCG. (4), (5) = Vdiff.
Fig.7
Current foldback characteristic; stabilized output voltage (VO) as function of load current (IO).
handbook, full pagewidth
Ic
Vmv x y VTCG Vdiff Vmv external peak-current setting (pin 7)
Ic (max)
I c (min)
V ref V fb
MCD407
Vss + V Ton(min)
The voltage Vmv determines the collector peak current Ic of transistor T1. The right-hand curve is passed through at start-up. When the feedback voltage slowly increases from zero, the peak current starts at Ic(min) and rises along the straight line until Ic(max) is reached. At a slightly higher feedback voltage the regulation slope is reached, which is approximately Vref. The plateau of the top between the points x and y has to be kept as small as possible. The voltage Vdiff decreases with the decreasing load. For good no-load operation the peak current has to be made zero with Vdiff. Due to the characteristic of the TCG open- and short-circuit feedback loop will result in low peak current. An additional signal on pin 13 can be supplied which is subtracted from the signal Vmv. This input can be used for feed forward information. If no feed forward information is used, pin 13 should be connected to ground.
Fig.8 Characteristics of the control part.
March 1994
8
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
Pulse width modulator (Block IV) The pulse width modulator compares the control voltage Vr with the sawtooth voltage Vsim. If Vsim > Vr output sub-section 8 is HIGH the LED is switched on and then the switching transistor is switched off. In this way the output voltage is controlled. EXAMPLE If the load decreases, VO increases and therefore Vr decreases. This causes the LED to start conducting prematurely, which implies that the switching transistor is turned off sooner. The consequence is that the collector peak current decreases and hence less energy is stored in the transformer and VO will decrease. LED control (Block V) If either output of sub-section 8 or output of sub-section 16 are HIGH the LED is conductive. In order to improve the start-up behaviour of the power supply, the demagnetization signal of sub-section 12 will only activate the LED driver if flip-flop (13) has previously been set. The set signal is generated in the following three ways. 1. Pulse width modulator (sub-section 8) 2. Comparator (18) 3. VP(min) detector Set signal (2.) and (3.) are added as extra security to guarantee a demagnetization pulse in the event of the switching transistor not having enough base current. In that situation e.g. at start-up, no comparator signal, set signal (3.) is generated by sub-section 8. Over voltage protection (Block VIII) The operation of the over voltage protection circuit is, in the event of the IC being SOPS-supplied, quite different from when the IC is externally supplied. LED driver (Block VI) The LED driver (pin 2) is blocked if the supply voltage VP is in the initialization phase (see Fig.4). The output stage is a push-pull stage, which can sink 5 mA and source 10 mA. Slow-start circuit (Block VII) The slow-start circuit is active at start-up, over voltage protection or after an overload (short-circuited), and stand-by mode. The voltage Vss and therefore the voltage Vmv and the peak current Ic slowly increase at start-up. By means of sub-section 27 the slow start voltage Vss is clamped to the voltage Vfb. If the feedback voltage is reduced, e.g. as overload, the slow-start capacitor is discharged to the level of Vfb. In this way a slow start-up is also guaranteed after an overload, short-circuit situation or after a stand-by mode. The circuit of sub-section 27 is not active during an over voltage protection. When the supply voltage VP is below the reset-level of 5.2 V (sub-section 28) the slow-start capacitor is quickly discharged. The slow-start input (pin 7) can also be used for Ic(max) setting by connecting a resistor to this pin.
TDA8385
OPERATION WHEN THE IC IS
EXTERNALLY SUPPLIED
When the voltage on pin 8 exceeds 2.5 V the slow-start capacitor is slowly discharged. During discharge the LED is permanently conducting. Discharge is stopped when Vss is below 115 mV. Flip-flop (23) will then be reset and the circuit is ready again for a new slow-start procedure. During an over voltage sub-section 27 is not active so that the output voltage VO cannot influence the slow-start discharge procedure. OPERATION WHEN IC IS SOPS-SUPPLIED (SEE FIGS 9 AND 10) When the voltage on pin 8 exceeds 2.5 V the slow-start capacitor is slowly discharged. During discharge of Css the supply capacitor CP is also discharged. Because the capacitors CP and Css have almost the same value and the supply current IP (15 mA) is much larger than the slow discharge current (50 A), the LED will be switched off by means of the VP(min) detection circuit (5.2 V). At that moment the switching transistor will be switched on again until the 7.5 V level is reached. During this hysteresis interval the slow-charge capacitor is quickly discharged. At the 7.5 V level the LED will be switched on again because flip-flop (23) output is still HIGH. The same procedure will be repeated several times until the slow-start capacitor reaches the 115 mV reset level. At that moment the slow-start procedure is started again. If there is still an over voltage the procedure will be repeated. Figure 10 is a detailed exposure of Fig.11.
March 1994
9
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
TDA8385
handbook, full pagewidth
Ic
(1)
t
Vss
(1) For detail see Fig.10.
t
MCD408
Fig.9 Over voltage protection.
VP (V) 7.5 V 5.2 V 0 t t delay Vss (V) slow discharge
quick discharge 0 t
Ic
t
Q FF23
t
MCD409
Fig.10 Detailed over voltage protection of Fig.9.
March 1994
10
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
Stand-by circuit (Block IX)
TDA8385
During stand-by operation the voltage Vsb is supplied from the SOPS via thyristor TH1 (see Fig.16). In the stand-by state, SOPS operates in a burst mode. When the voltage on pin 10 exceeds 2.5 V the LED driver is permanently activated. The LED driver is released again if the voltage is below 2 V (see Fig.11).
handbook, full pagewidth
Vsb (V)
2.5 V
2V
0
t
output sub-section 25
0 t
I LED (mA) 5 mA
0 t
MCD410
Fig.11 Stand-by operation; burst mode.
March 1994
11
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
Regulation indicator output (Block X)
TDA8385
Pin 1 can be used to reset the logic circuit in the TV receiver at power on and off. Sub-section 29 has an open-collector output. The output of this block is LOW during the regulation mode (Vdiff < Vts; see Fig.12).
handbook, full pagewidth
V
Vfb Vts
2.5
0
t
Vdiff VP
0
t
V VRIO : open-collector output RIO
0
t
MCD411
A desired delay at power-on reset can be made externally.
Fig.12 Regulation indicator output; pin 1.
March 1994
12
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
TDA8385
LIMITING VALUES In accordance with the Absolute Maximum Rating System (IEC 134). All voltages are measured with respect to ground; positive current flow into the IC; all pins not mentioned in the voltage list are not allowed to be voltage driven. The voltage ratings are valid provided other ratings are not violated; current ratings are valid provided the power rating is not violated. SYMBOL Voltages VP Vn V3 V8,10 V12 V15 Currents I1 In I3 I5, 6 I7 I11 I16 Temperatures Tamb Tstg Ptot operating ambient temperature storage temperature -25 -55 - +70 +150 C C current on pin 1 current on pins 2, 12 and 15 current on pin 3 current on pins 5 and 6 current on pin 7 current on pin 11 current on pin 16 0 -10 -1 -1 -1 -10 0 2 +10 0 +1 +25 +0.5 20 mA mA mA mA mA mA mA supply voltage pin 2 connected pin 2 open-circuit voltage on pins 1, 2, 4, 7, 9 and 13 voltage on pin 3 voltage on pins 8 and 10 voltage on pin 12 voltage on pin 15 -0.5 -0.5 -0.5 -0.5 -0.5 -0.1 -0.5 20 18 +18 +6 +3.9 +0.5 +0.5 V V V V V V V PARAMETER CONDITIONS MIN. MAX. UNIT
Power dissipation total power dissipation 500 mW
THERMAL RESISTANCE SYMBOL Rth j-a PARAMETER from junction to ambient in free air THERMAL RESISTANCE 55 K/W
March 1994
13
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
CHARACTERISTICS VP = 15 V; I3 = 200 A; Tamb = 25 C; unless otherwise specified. SYMBOL Supply VP V16 V16(hys) I16 V11 V3 V9 I9 I11 I11 Go B V9/T V5 supply voltage (pin 16) supply initialization level internal fixed hysteresis supply current supply voltage ripple rejection active LED output see Figs 13 and 14 7.9 7.1 2.5 - - - 7.5 - - 60 20 7.9 PARAMETER CONDITIONS MIN. TYP.
TDA8385
MAX.
UNIT
V V V mA mV
2.55 20 -
Reference voltage reference voltage at pin 3 0.52 0.55 0.58 V
Error amplifier threshold voltage error amplitude input current feedback input sink current output source current output open loop gain unity gain bandwidth temperature coefficient threshold for switching output Vdiff = 1.25 V; V4 = 2 V; V13 = 0 V; V7 > V9; I2 = 2 mA V4 = 0.5 V V4 = 0.5 V; V13 = 0 V; V7 > V9; I2 = 2 mA V9 = 0 V V9 = 0.4 V V9 = 1 V V9 = 1.6 V V9 = 2.25 V note 2 0.4 - Vos - 1.4 - Vos - 2.4 - Vos - 0.5 - Vos 0.9 - Vos 1.5 - Vos 2.1 - Vos - - 0.6 - Vos - 1.6 - Vos - 2.6 - Vos 700 V V V V V ns V11 = 80 mV V11 = 2.5 V 2.4 - 400 500 - - - - 2.5 - - - 100 600 300 x Vdiff - 10-6 Vos(1) 2.6 0.5 - - - - - - V A A A dB kHz K-1 V
Transfer characteristic generator I4/I3 V5 current ratio threshold for switching output Ton(min) Vfb = 20% Vfb = 50% Vfb = 80% clamp tPLH response time pulse width modulation pin 5 to pin 2 LOW-to-HIGH response time pulse width modulation pin 5 to pin 2 HIGH-to-LOW 0.23 0.25 0.27
tPHL
note 2
-
-
1
s
Feed forward V5 threshold for switching output (Vfo) input bias current V4 = 0.5 V; V13 = 0 V; 0.6 - Vos V7 = V9 = 3 V; I2 = 2 mA; V11 = 1 V V13 = 0 V - 0.7 - Vos 0.8 - Vos V
I13
-
1
A
March 1994
14
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
SYMBOL Slow-start I7/I3 I7 V7 V5 charge current ratio quick discharge current clamping level threshold for switching output (Vss) V7 = 0.5 V V7 = 1 V V7 = 100 mV I7 = 100 A 0.22 20 50 2.8 0.24 - - 3.0 1.5 - Vos PARAMETER CONDITIONS MIN. TYP.
TDA8385
MAX.
UNIT
0.26 - - 3.2 1.6 - Vos mA A V V
V4 = 0.5 V; V13 = 0 V; 1.4 - Vos V7 = 1 V; I2 = 2 mA; V9 = 2 V I2 = 2 mA V2 = 2 V 4.8 - I2 = 5 mA 12 -
Output stage V2(sat) I2 saturation voltage source current operating initialization phase V2 I5/I12 V12 V5(sat) open output voltage HIGH Current simulation current ratio simulation input voltage saturation voltage V5 = 1 V; I12 = 0.5 mA 0.19 I12 = 0.5 mA V15 = V6 = 0 V; I5 = 1 mA V15 = V6 = 0 V; I5 = 200 A V threshold for switching output; voltage difference between pins 5 and 11; offset simulation voltage (Vos) delay from pin 15 to pin 5 LOW-to-HIGH delay from pin 15 to pin 5 HIGH-to-LOW clamping level positive negative V15 C15 I15 demagnetization threshold voltage input capacitance input bias current V15 = 60 mV - - - 0.2 - - - 100 0.21 1.1 300 200 140 V mV mV mV - 5.3 - - 300 6.3 50 - mV mA A V
V4 = 0.5 V; V13 = 0 V; 60 V7 = V9 = 3 V; I2 = 2 mA; V11 = 0.5 V see Fig.15; pin 6 not connected see Fig.15 I15 = 10 mA - - 90 - - - -
Demagnetization input tdemLH tdemHL V15 - - 500 1 ns s
- - 115 - -
1.2 -1 140 10 0.5
V V mV pF A
March 1994
15
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
SYMBOL Delay setting I6/I3 I6 V6 V6(sat) tdLH charge current ratio clamping level saturation voltage delay from pin 6 to pin 2; V6 crossing the 2.5 V level; LOW-to-HIGH V15 = 140 mV C6 = 470 pF; V5 = 0 V; I2 = 2 mA; V15 see Fig.15; excluding capacitive tolerances V6 = 2.5 V; I3 = 250 A V6 = 1 V 1.1 2 2.8 - - 1.2 - - 50 - 1.3 - 3.2 100 1.2 charge current initialization phase V6 = 1 V; V16 = 5 V PARAMETER CONDITIONS MIN. TYP.
TDA8385
MAX.
UNIT
mA V mV s
t/c Stand-by V10H V10(hys) tdLH tdHL I10 V8 tdLH tdHL V7 I7/I3 I8 V1 I1 Notes
delay setting (t = C6 x V/I)
-
10
-
ns/pF
threshold level HIGH hysteresis delay to output pin 10 to pin 2 LOW-to-HIGH delay to output pin 10 to pin 2 HIGH-to-LOW input current V10 = 2.3 V
2.4 450 - - -
2.5 500 - - -
2.6 550 1 1 5
V mV s s A
Over voltage protection threshold level delay to output pin 8 to pin 2 LOW-to-HIGH delay to output pin 8 to pin 2 HIGH-to-LOW reset level slow discharge current ratio input current V7 = 1 V V8 = 3 V I1 = 1 mA V1 = V16 2.4 - - 90 0.12 - - - 2.5 - - - 0.23 - - - 2.6 1 1 140 0.31 1 A V s s mV
Regulation indicator output saturation voltage leakage current 300 1 mV A
1. Vos = Voffset. 2. V5 pulse = 1 V; V4 = 0.5 V; V9 = V7 = 3 V; V11 = 0.5 V; V13 = 0 V; I2 = 2 mA.
March 1994
16
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
TDA8385
VP
Vdiff (pin 11) 15 V 2V ~ 3V ~
t
MCD412
t
MCD413
Frequency = 50 kHz. Slew rate = 0.2 s.
Frequency = 50 kHz. Slew rate = 0.2 s.
Fig.13 Supply voltage ripple rejection; VP as a function of time.
Fig.14 Supply voltage ripple rejection; Vdiff as a function of time.
Table 1 Condition of test circuit used for Figs 13 and 14. PINS 1, 2, 4 to 6, 12, 13 8 to 10, 14, 15 3 7 16 11 ground Rref = 2.7 k Css = 4.7 F VP; see Fig.13 Vdiff; see Fig.14 STATUS not connected
March 1994
17
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
TDA8385
115 mV
handbook, full pagewidth
~ + 0.8 V ~ demagnetization input (pin 15) 0V
~ - 0.8 V ~
90% peak-current setting input (pin 5) 10%
1V
0V
t demLH
t demHL
MCD414
Fig.15 Timing diagram; demagnetization delay time.
March 1994
18
handbook, full pagewidth
March 1994
Vf VO ns Co TH1 np R15 A Ic 15 10 16 T1 RC 5 12 14 6 4 7 3 TDA8385 9 11 V stab
Philips Semiconductors
APPLICATION INFORMATION
Control circuit for a Self-Oscillating Power Supply (SOPS)
VI (mains)
8 2 1 13 1/2 CNR50
19
A VP C Cdelay nh R12 CP
1/2 CNR50
C ss R ref
MCD415
R Ton(min)
TDA8385
Preliminary specification
Fig.16 Application circuit of SOPS with stand-by facility.
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
TDA8385
handbook, full pagewidth
VO Vf
ns V np I Ic
Ton
Toff storage time and delay (SOPS)
output sub-section 11
output sub-section 12 DEMAGNETIZATION
RESET (sub-section 13)
delay
Vc Vsim
V r (output sub-section 7) Vsim (output sub-section 10) comparator (18) level = 1 V
output sub-section 8 COMPARATOR
SET (sub-section 13)
output sub-section 13 Q
output sub-section 16 DEMAGNETIZATION
output sub-section 14 LED driver t
MCD416
Fig.17 Application timing diagram.
March 1994
20
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
PACKAGE OUTLINE
TDA8385
seating plane
22.00 21.35
8.25 7.80
5.1 max 1.2 min 3.9 3.4 2.2 max
2.54 (14x) 1.4 max
0.53 max
0.254 M
0.32 max 7.62 9.5 8.3
MSA349
16
9 6.48 6.14
1
8
Dimensions in mm.
Fig.18 16-lead dual in-line; plastic with internal heat spreader; opposite bent leads (SOT38WBE).
March 1994
21
Philips Semiconductors
Preliminary specification
Control circuit for a Self-Oscillating Power Supply (SOPS)
SOLDERING Plastic dual in-line packages BY DIP OR WAVE The maximum permissible temperature of the solder is 260 C; this temperature must not be in contact with the joint for more than 5 s. The total contact time of successive solder waves must not exceed 5 s. DEFINITIONS Data sheet status Objective specification Preliminary specification Product specification Limiting values The device may be mounted up to the seating plane, but the temperature of the plastic body must not exceed the specified storage maximum. If the printed-circuit board has been pre-heated, forced cooling may be necessary immediately after soldering to keep the temperature within the permissible limit.
TDA8385
REPAIRING SOLDERED JOINTS Apply a low voltage soldering iron below the seating plane (or not more than 2 mm above it). If its temperature is below 300 C, it must not be in contact for more than 10 s; if between 300 and 400 C, for not more than 5 s.
This data sheet contains target or goal specifications for product development. This data sheet contains preliminary data; supplementary data may be published later. This data sheet contains final product specifications.
Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability. Application information Where application information is given, it is advisory and does not form part of the specification. LIFE SUPPORT APPLICATIONS These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such improper use or sale.
March 1994
22

▲Up To Search▲

Price & Availability of TDA8385

	To Download TDA8385 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .