Philips Semiconductors Preliminary specification Control circuit for a Self-Oscillating Power Supply (SOPS) TDA8385 • Over-load current fold back characteristic FEATURES • Bandgap reference generator GENERAL DESCRIPTION • LED driver • 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 • Demagnetization protection • Programmable determination of switch-on moment of switching transistor for low-switching losses The TDA8385 is intended to be used in combination with the opto-coupler (CNR50) as a control unit for a self-oscillating power supply. • Feed-forward input • Regulation-indicator output • Programmable minimum on-time of switching transistor • Accurate peak-current setting. ORDERING INFORMATION PACKAGE EXTENDED TYPE NUMBER PINS PIN POSITION MATERIAL CODE TDA8385 16 DIL plastic SOT38WBE March 1994 2 Philips Semiconductors Preliminary specification Control circuit for a Self-Oscillating Power Supply (SOPS) TDA8385 BLOCK DIAGRAMS VP GND handbook, full pagewidth 16 14 latch current reference setting 3 I ref REFERENCE BLOCK V P (min) DETECTOR STABILIZED SUPPLY 2 1 28 reset (28, 27, 23) I ref feed forward input Vstab Vref I SUPPLY REFERENCES 13 V fo V ts regulation indicator output differential amplifier output 1 RIO 29 REGULATION INDICATOR 7 X Vmv 11 V diff DIFFERENTIAL AMPLIFIER Vref (2.5 V) V diff V ts 3 feedback voltage input 9 V TCG CLAMP Vfb MINIMUM VOLTAGE CLAMP TCG 50 µA 2.5 V CONTROL PART 4 transistor-on setting input III T 4 on(min) 50 µA charge 5 Vss + Ton (min) slow start voltage input 6 7 19 Vss reset (28) quick discharge 27 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) handbook, full pagewidth TDA8385 stand-by voltage input Vsb 10 TDA8385 latch latch 2.5 V 2V LED OUTPUT STAGE 25 2 LED driver output 15 2.5 V STAND-BY Vr IX 17 PWM 8 Vsim VI LED DRIVER IV Q (23) comparator 18 (28) S FF 14 16 demagnetization R 26 Q 13 V LED CONTROL demagnetization I sim 0.2 I 12 Vc I12 9 12 5 I peak DEM 15 11 DELAY 6 10 demagnetization input delay setting II SAWTOOTH GENERATOR (17) 100 µA slow discharge peak-current setting input 115 mV 12 100 mV current simulation input (28) Q R 24 115 mV 21 FF 23 S Q over voltage 8 22 2.5 V VIII OVER-VOLTAGE PROTECTION MCD418 Fig.2 Block diagram; part B (continued from Fig.1; part A). March 1994 4 over-voltage protection Philips Semiconductors Preliminary specification Control circuit for a Self-Oscillating Power Supply (SOPS) TDA8385 PINNING SYMBOL PIN DESCRIPTION RIO 1 regulation indicator output LED 2 LED driver output Iref 3 current reference setting Ton(min) 4 transistor-on setting input Ipeak 5 peak current setting input DELAY 6 delay setting Vss 7 slow start voltage input OVP 8 over-voltage protection Vfb 9 feedback voltage input Vsb 10 stand-by voltage input Vdiff 11 differential amplifier output Isim 12 current simulation input Vfo 13 feed forward input GND 14 ground (0 V) DEM 15 demagnetization input VP 16 positive supply voltage 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. DESCRIPTION I supply references II sawtooth generator III control part IV pulse width modulator (PWM) V LED control VI LED driver VII slow-start circuitry VIII over-voltage protection IX stand-by circuit X regulation-indicator output These 10 functional blocks of Fig.1 and Fig.2 contain sub-sections numbered 1 to 28 which are March 1994 handbook, 2 columns 1 16 V P LED 2 15 DEM I ref 3 14 GND Ton(min) 4 RIO 13 Vfo TDA8385 I peak 5 12 I sim DELAY 6 11 Vdiff Vss 7 10 Vsb OVP 8 9 V fb MCD402 Fig.3 Pinning diagram. 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 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. Philips Semiconductors Preliminary specification Control circuit for a Self-Oscillating Power Supply (SOPS) TDA8385 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. latch initialization operation 5.2 VI nh I sim = p × ------ × ----------n p R12 (2) I sim R12 12 L np I 12 nh 5 Ic sw1 T1 Where: p = reflection factor; I sim p = -------- = 0.2 I 12 MCD403 Fig.4 Latch initialization as a function of supply voltage VP. VI (1) 20 V P (V) For the voltage Vc yields: I sim × T on V c = -----------------------C 7.5 Vc C Vc (2) → (1) gives: t VI p nh V c = ---- × ------ × ----------- × T on C n p R12 Ton (3) 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 × C × n p × R12 T on = ---------------------------------------------p × nh × VI (4) For the primary current Ic yields: VI I c = ----- × T on L (5) Substitution (4) into (5): C 1 np I c = ---- × --- × ------ × R12 × V c L p nh (6) 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. TDA8385 DELAY SETTING (PIN 6) Control part (Block III) 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 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 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. 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. 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 (3) V clamp Vmv • 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). (4) (2) V Ton(min) (1) (5) Vfb MCD405 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 (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. (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 Some relevant characteristics of the control part are depicted in Fig.8. Vmv Ic (max) x y VTCG Vdiff Vmv external peak-current setting (pin 7) I c (min) V ref Vss + V Ton(min) V fb MCD407 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. TDA8385 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) 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) 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. 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. 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 µA), 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 t (1) For detail see Fig.10. MCD408 Fig.9 Over voltage protection. VP (V) 7.5 V 5.2 V 0 t t delay slow discharge Vss (V) 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) TDA8385 Stand-by circuit (Block IX) 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) TDA8385 Regulation indicator output (Block X) 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 PARAMETER CONDITIONS MIN. MAX. UNIT Voltages VP supply voltage pin 2 connected −0.5 20 V pin 2 open-circuit −0.5 18 V V Vn voltage on pins 1, 2, 4, 7, 9 and 13 −0.5 +18 V3 voltage on pin 3 −0.5 +6 V V8,10 voltage on pins 8 and 10 −0.5 +3.9 V V12 voltage on pin 12 −0.1 +0.5 V V15 voltage on pin 15 −0.5 +0.5 V I1 current on pin 1 0 2 mA In current on pins 2, 12 and 15 −10 +10 mA I3 current on pin 3 −1 0 mA I5, 6 current on pins 5 and 6 −1 +1 mA I7 current on pin 7 −1 +25 mA I11 current on pin 11 −10 +0.5 mA I16 current on pin 16 0 20 mA Tamb operating ambient temperature −25 +70 °C Tstg storage temperature −55 +150 °C − 500 mW Currents Temperatures Power dissipation Ptot total power dissipation THERMAL RESISTANCE SYMBOL Rth j-a March 1994 PARAMETER THERMAL RESISTANCE from junction to ambient in free air 55 K/W 13 Philips Semiconductors Preliminary specification Control circuit for a Self-Oscillating Power Supply (SOPS) TDA8385 CHARACTERISTICS VP = 15 V; I3 = 200 µA; Tamb = 25 °C; unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT Supply VP supply voltage (pin 16) 7.9 − 20 V V16 supply initialization level 7.1 7.5 7.9 V V16(hys) internal fixed hysteresis 2.5 − 2.55 V I16 supply current active LED output − − 20 mA V11 supply voltage ripple rejection see Figs 13 and 14 − 60 − mV 0.52 0.55 0.58 V Reference voltage V3 reference voltage at pin 3 Error amplifier V9 threshold voltage error amplitude 2.4 2.5 2.6 V I9 input current feedback input − − 0.5 µA I11 sink current output V11 = 80 mV 400 − − µA I11 source current output V11 = 2.5 V 500 − − µA Go open loop gain − 100 − dB B unity gain bandwidth − 600 − kHz 10−6 − K−1 Vos(1) − V ∆V9/∆T V5 temperature coefficient − ±300 × threshold for switching output Vdiff = 1.25 V; V4 = 2 V; V13 = 0 V; V7 > V9; I2 = 2 mA − Vdiff − 0.23 0.25 0.27 Transfer characteristic generator I4/I3 current ratio V4 = 0.5 V V5 threshold for switching output V4 = 0.5 V; V13 = 0 V; V7 > V9; I2 = 2 mA Ton(min) V9 = 0 V 0.4 − Vos 0.5 − Vos 0.6 − Vos V Vfb = 20% V9 = 0.4 V − 0.9 − Vos − V Vfb = 50% V9 = 1 V 1.4 − Vos 1.5 − Vos 1.6 − Vos V Vfb = 80% V9 = 1.6 V − 2.1 − Vos − V 2.4 − Vos − 2.6 − Vos V tPLH response time pulse width modulation pin 5 to pin 2 LOW-to-HIGH note 2 − − 700 ns tPHL response time pulse width modulation pin 5 to pin 2 HIGH-to-LOW note 2 − − 1 µs 0.7 − Vos 0.8 − Vos V − 1 µA clamp V9 = 2.25 V Feed forward V5 threshold for switching output (Vfo) V4 = 0.5 V; V13 = 0 V; 0.6 − Vos V7 = V9 = 3 V; I2 = 2 mA; V11 = 1 V I13 input bias current V13 = 0 V March 1994 − 14 Philips Semiconductors Preliminary specification Control circuit for a Self-Oscillating Power Supply (SOPS) SYMBOL PARAMETER TDA8385 CONDITIONS MIN. TYP. MAX. UNIT Slow-start I7/I3 charge current ratio I7 quick discharge current V7 = 0.5 V 0.22 0.24 0.26 V7 = 1 V 20 − − mA V7 = 100 mV 50 − − µA 2.8 3.0 3.2 V 1.5 − Vos 1.6 − Vos V − 300 mV V7 clamping level I7 = 100 µA V5 threshold for switching output (Vss) V4 = 0.5 V; V13 = 0 V; 1.4 − Vos V7 = 1 V; I2 = 2 mA; V9 = 2 V Output stage V2(sat) saturation voltage I2 = 2 mA I2 source current V2 = 2 V V2 − operating 4.8 5.3 6.3 mA initialization phase − − 50 µA 12 − − V open output voltage HIGH I2 = 5 mA Current simulation I5/I12 current ratio V5 = 1 V; I12 = 0.5 mA 0.19 0.2 0.21 V12 simulation input voltage I12 = 0.5 mA − − 1.1 V V5(sat) saturation voltage V15 = V6 = 0 V; I5 = 1 mA − − 300 mV V15 = V6 = 0 V; I5 = 200 µA − − 200 mV 100 140 mV ∆V threshold for switching output; voltage difference between pins 5 and 11; offset simulation voltage (Vos) V4 = 0.5 V; V13 = 0 V; 60 V7 = V9 = 3 V; I2 = 2 mA; V11 = 0.5 V Demagnetization input tdemLH delay from pin 15 to pin 5 LOW-to-HIGH see Fig.15; pin 6 not connected − − 500 ns tdemHL delay from pin 15 to pin 5 HIGH-to-LOW see Fig.15 − − 1 µs V15 clamping level I15 = 10 mA positive − − 1.2 V negative − − −1 V 90 115 140 mV V15 demagnetization threshold voltage C15 input capacitance I15 input bias current March 1994 V15 = 60 mV 15 − − 10 pF − − 0.5 µA Philips Semiconductors Preliminary specification Control circuit for a Self-Oscillating Power Supply (SOPS) SYMBOL PARAMETER TDA8385 CONDITIONS MIN. TYP. MAX. UNIT Delay setting I6/I3 charge current ratio V6 = 1 V 1.1 1.2 1.3 I6 charge current initialization phase V6 = 1 V; V16 = 5 V 2 − − mA V6 clamping level 2.8 − 3.2 V V6(sat) saturation voltage V15 = 140 mV − 50 100 mV tdLH delay from pin 6 to pin 2; V6 crossing the 2.5 V level; LOW-to-HIGH C6 = 470 pF; V5 = 0 V; I2 = 2 mA; V15 see Fig.15; excluding capacitive tolerances − − 1.2 µs t/c delay setting (t = C6 × V/I) V6 = 2.5 V; I3 = 250 µA − 10 − ns/pF Stand-by V10H threshold level HIGH 2.4 2.5 2.6 V V10(hys) hysteresis 450 500 550 mV tdLH delay to output pin 10 to pin 2 LOW-to-HIGH − − 1 µs tdHL delay to output pin 10 to pin 2 HIGH-to-LOW − − 1 µs I10 input current − − 5 µA V10 = 2.3 V Over voltage protection V8 threshold level 2.4 2.5 2.6 V tdLH delay to output pin 8 to pin 2 LOW-to-HIGH − − 1 µs tdHL delay to output pin 8 to pin 2 HIGH-to-LOW − − 1 µs V7 reset level 90 − 140 mV I7/I3 slow discharge current ratio V7 = 1 V 0.12 0.23 0.31 I8 input current V8 = 3 V − − 1 µA Regulation indicator output V1 saturation voltage I1 = 1 mA − − 300 mV I1 leakage current V1 = V16 − − 1 µA Notes 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 t ~ ~ 3V 2V t MCD412 Frequency = 50 kHz. Slew rate = 0.2 µs. Frequency = 50 kHz. Slew rate = 0.2 µs. 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 STATUS not connected 8 to 10, 14, 15 ground 3 Rref = 2.7 kΩ 7 Css = 4.7 µF 16 VP; see Fig.13 11 Vdiff; see Fig.14 March 1994 MCD413 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 1V 90% peak-current setting input (pin 5) 10% t demLH t demHL Fig.15 Timing diagram; demagnetization delay time. March 1994 18 0V MCD414 VI (mains) 1/2 CNR50 March 1994 Ic T1 nh TH1 R12 19 CP VP RC V stab Co R15 12 14 16 10 15 9 5 C 6 Cdelay 4 TDA8385 11 1 2 R ref 13 3 R Ton(min) C ss 7 8 VO MCD415 1/2 CNR50 Control circuit for a Self-Oscillating Power Supply (SOPS) handbook, full pagewidth Fig.16 Application circuit of SOPS with stand-by facility. A A np ns Vf Philips Semiconductors Preliminary specification TDA8385 APPLICATION INFORMATION Philips Semiconductors Preliminary specification Control circuit for a Self-Oscillating Power Supply (SOPS) TDA8385 VO handbook, full pagewidth Vf Ton ns V np I Toff storage time and delay (SOPS) Ic output sub-section 11 RESET (sub-section 13) output sub-section 12 DEMAGNETIZATION delay Vc V r (output sub-section 7) Vsim comparator (18) level = 1 V Vsim (output sub-section 10) 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 Fig.17 Application timing diagram. March 1994 20 MCD416 Philips Semiconductors Preliminary specification Control circuit for a Self-Oscillating Power Supply (SOPS) TDA8385 PACKAGE OUTLINE 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) 0.53 max 0.254 M 0.32 max 7.62 1.4 max 9.5 8.3 MSA349 16 9 6.48 6.14 8 1 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. TDA8385 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. 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. DEFINITIONS Data sheet status Objective specification This data sheet contains target or goal specifications for product development. Preliminary specification This data sheet contains preliminary data; supplementary data may be published later. Product specification This data sheet contains final product specifications. Limiting values 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