POWER INTEGRATED CIRCUIT Switching Regulator 15 Amp Positive and Negative Power Output Stages FEATURES Designed and characterized for switching regulator applications Cost saving design reduces size, improves efficiency, reduces noise and RFI (See note 4.) High operating frequency (to >100kHz) results in smaller inductor-capacitor filter PIC625 PIC626 PIC627 PIC635 PIC636 PIC637 and improved power supply response time High operating efficiency: Typical 7A circuit performance Rise and Fall time <300 ns Efficiency >85% No reverse recovery spike generated by commutating diode (See note 4. and Fig. 2.) Electrically isolated, 4-Pin, TO66 hermetic case DESCRIPTION The Unitrode ESP Switching Regulator is a unique hybrid transistor circuit, specifically designed, constructed and specified for use in high current switching regulator appli- cations. The designer is thus relieved of one of the most time consuming, tedious and critical aspects of switching regulator design: choosing the appropriate switching transistors and commutating diode, and empirically determining the optimum drive and bias conditions. Switching regulators, when compared to conventional regu- lators, result in significant reductions in size, weight, and internal power losses and a major decrease in overall cost. Using the Unitrode PIC600 series the designer can achieve further improvements in size, weight, efficiency, and costs. At the same time, because of the PIC600 series design and packaging, the designer is aided in overcoming two of the most significant drawbacks to switching regulators: noise generation and slow response time; there is, in fact, no diode reverse recovery spike (See note 4.). The PIC600 series switching regulators are designed and characterized to be driven wih standard integrated circuit voltage regulators. They are completely characterized over their entire operating range of 55C to +125C. The devices are enclosed in a special 4-pin TO66 package, hermetically sealed for high reliability. The hybrid circuit construction utilizes thick film resistors on a beryllia substrate for maximum thermal conductivity and resultant low thermal impedance. All of the active elements in the hybrid are fully passivated. Application Notes U-68 and U-76 provide a detailed descrip- tion of the hybrid circuit and design guidance for specific circuit applications. PIC625 SCHEMATIC PiC635 PIC626 PIC636 POS. 4 Ples27 1 POS. NEG. 4 PIC637 1 NEG. INPUT y) OUTPUT INPUT OUTPUT q | 3 2 3 2 DRIVE COMMON DRIVE COMMON MECHANICAL SPECIFICATIONS NOTES: 1. Case is electrically isolated. 2. Loads may be soldered to within 1fig Of base provided temperature- PIC625 PIC626 PIC627 PIC635 PIC636 PICG37 4-Pin TO-66 time exposure is less than 260C { ins. mm 620 MAX. 15.75, MAX. for 10 seconds. A B {060-075 [227-191 S ) B F | 028-034 0.71-0.86 ev ) {- af je ORIVE(3) 0 [968-962 [243-24 43 \ Cex INPUT(4) = | 0-210 0 | E 7 G F [190-210 [483-893 | dk \ G 350 MAX. 8.89 MAX. RAD. d,s} f | H [so-so [eas rage y z H J | .142-.152 OIA. [9.61-3.36 DIA. + [s ls. COMMON(2) L OUTPUT(1) 4/79 200 ms UNITRODEPIC625 PIC626 PIC627 PIC635 PIC636 PIC637 ABSOLUTE MAXIMUM RATINGS Pic625 Prcez6 PIC627 PIC635 PIC36 PIC637 Input Voltage, V,., ...... 60V. 80V. . 100V Output Voltage, V,.. .... . 60V. 80V.. 100V Drive-Input Reverse Voltage, V;., . 5V, . 5V.. . 5A Output Current, |, 1A.. 15A Drive Current, Ll, .... QAR. O4A Thermal Resistance Junction to Case, 6). Power Switch . cee eee ee nteeeeen . . voces AOPC/W...... Commutating Diode . . . . we AOC PW cee Case to Ambient, 6_,.. ... ve coctetttiuieeescuesteees bieeie ttn ceever, 60,0C/W. Operating Temperature Range, T. . . bows bectseseees cove =H5C to 4128C. ve Maximum Junction Temperature, Tj . . . cee ee teeeseensees ve RUSOER Coc ececseeete terete Storage Temperature Range . bce ae cette we 65C to +150C.. ELECTRICAL SPECIFICATIONS (at 25C unless noted) P1C625/626/627 P1C635/636/637 Test Symbot Min. | Typ. |Max. iMin. | Typ. Max. |Units Conditions Current Delay Time ta; {| 35] 60 | | 35 60 ns | V,, = 25V(25V) Current Rise Time t.; | 65 | 150 | ; 65 | 175 | ns| V,,,=5V(5V) Voltage Rise Time ty | 40} 6 ;J| 40 60 ns} lo == 7A(7A) Voltage Storage Time t, ~ | 900} | ] 900 | | ns] 1, = 30MA(30mA) Voltage Fall Time t,, | 70 | 175 | j} 100 | 300 | ns| See Figure 2 Current Fall Time ty; {| 175; 300 | | 175 | 300 | ns| See notes 1, 2,4 Efficiency (Notes 2 and 4) 2 85 a _ 85 _ % On-State Voltage (Note 3) Veifon) | | LO} 25 | | L0}L5]) V | 1,=7A(7A), |, = .03A(.03A) On-State Voltage (Note 3) Vee ttons | 25 | 35 | | +25 |-35| Vi t,= 15A(15A), f, = .03AC03A) Diode Fwd. Voltage (Note 3) Vo. tton} | 85 | 125) | 85 |125) Vi] t,=7A(7A) Diode Fwd. Voltage (Note 3) 2-Ifon} | 95 | 1.75 | | .95 |1.75; Vi 1, =15A(15A) Oif-State Current by | 01) 10 | | 01 | 10) uA} V, = Rated input voltage Off-State Current an | 10; | ~; -l0} wA| V, = Rated input voltage, T, = 100C Diode Reverse Current i, |} 10} 10 | } 10}]10] yA} V, = Rated output voltage Diode Reverse Current lp | 500; ; j| 500 | wA| V, = Rated output voltage, T, = 100C Notes: 1. In switching an inductive load, the current will lead the voltage on turn-on and lag the voltage on turn-off (see Figure 2.). Therefore, Voltage Delay Time (t,,) = ty, + t,, and Current Storage Time (t,)) = t,, + ,,. 2. The efficiency is a measure of internal power losses and is equal to Output Power divided by Input Power. The switching speed circuit ot Figure 1., in which the efficiency is measured, is representative of typical operating conditions for the PIC600 series switching regulators. 3. Pulse test: Duration = 300ms, Duty Cycle <2%. 4. As can be seen from the switching waveforms shown in Figure 2., no reverse or forward recovery spike is generated by the commutating diode during switching! This reduces self-generated noise, since no current spike is fed through the switching regulator. It also improves efficiency and reliability, since the power switch only carries current during turn-on. POWER DISSIPATION CONSIDERATIONS The total power losses in the switching regulator is the sum of the switching losses, and the power switch and diode D.C. losses. Once total power dissipation has been determined, the Power Dissipation curve, or thermal resistance data may be used to determine the allowable case or ambient temperature for any operating condition. The switching losses curve presents data for a frequency of 20KHz. To find losses at any other frequency, multiply by f/20KHz. The D.C. losses curves present data for a duty cycle of .2. To find D.C. losses at any other duty cycle, multiply by D/.2 for the power switch and by (1-D)/.8 for the diode. At frequencies much below 1OKHz the above method for determining the allowable case or ambient temperature becomes invalid and a detailed transient thermal analysis must be performed. Please request Design Note 6 (DN-6) for further information. UNITRODE CORPORATION + 5 FORBES ROAD LEXINGTON, MA 02173 + TEL. (617) 861-6540 TWX (710) 326-6509 TELEX 95-1064 201 PRINTEO IN U.S.A.PIC625 PIC626 PIC627 PIC635 PIC636 PIC637 Power Dissipation Efficiency 0 [ 100 fa the Vo 20V = 90 = % f = 20KHz,V,,, = 5V 80 T = 30 f = 50KHz,V,,, = 5V Xd & z 70 2 2 3 60 z Gi 20 3 50 2 N So a 1S \ i 40 g I Pa e 30 bas measured in the circuit shown ui 10 | Maximum allowable average in Figure 1. z power dissipation each, for the 20 + V,, = 25V { 5 | power switch and for the diode. | ac Maximum allowable case temperature = 125C FT. = 25C 0 1 1 1 t 1 ol Se se a 50 25 0 25 50 75 100 125 150 2 3 4 5 6 78910 15 20 T. + CASE TEMPERATURE (C} |, OUTPUT CURRENT {A) Diode D.C. Losses Power Switch D.C. Losses 100 var ) F Power Switch Duty Cycle -- 0.2 109 Duty Cycie = 0.2, |, = 30mA 50 f Diode Duty Cycle = 0.8 50 fT = 25C fT, = 25C 4 To obtain power switch losses at l To obtain diode tosses at any any other duty cycle, multiply by 20 f other duty cycle, multiply by + 20 + D/.2, where D is the duty cycle. (1-D}/.8 where D = Power ea = 10 tswite . Ky a = ESwitch Duty pele = 10 @ os p} tt 4 oO a [MAXIMUM TYPICAL | u no QS 5 rT Go, TYPICAL . L wl a 9 LT oS 1.0 bet a 1 5 os 2 2 10 A 2 3 4 5 6 7 8910 20 2 3. 4 5 6 78 910 20 1, OUTPUT CURRENT {A) Switching MAXIMUM SWITCHING LOSSES (W) 2 3 4 5 6 1, ~ OUTPUT CURRENT (A) Losses V,, = 25V, 1, = 30mA f = 20KHz Te. = 25C To determine switching losses at any other frequency, multiply by f/20KHz where f is the frequency at which the losses are to be determined. TYPICAL - 7 86910 20 {, OUTPUT CURRENT (A) UNITRODE CORPORATION 5 FORBES ROAD LEXINGTON, MA 02173 TEL. (617) 861-6540 TWX (710) 326-6509 TELEX 95-1064 202 PRINTED IN U.S.A.v,, - + PICS25 Vv PICG26 R= ow PIC627 7iso = 5V lorive == 30MA Pulse Width .= 10us Rep. Rate = 20kHz oe OO Figure 1. PIC625, 626, 627 Switching Speed Circuit On-State Characteristics MAXIMUM 1, ON-STATE CURRENT (A) 0 1 2 3 4 5 V,.,(on) ON-STATE VOLTAGE (V) Turn-on Time 1000 - . As measured in the circuit shown in Figure 1. 500 | Vin = 25 400 f Vou = 5V 1, = 30mA 300 } 73 T= 25C _. 200 a uw = 100 z | - 50 40 30 20 10 2 3 4 5 6 7 8910 20 1, OUTPUT CURRENT (A) UNITRODE CORPORATION 5 FORBES ROAD LEXINGTON, MA 02173 TEL. (617) 861-6540 TWX (710) 326-6509 + TELEX 95-1064 203 PIC625 PIC626 PiC627 PIC635 PiC636 PIC637 I, -~ DIODE FORWARD CURRENT (A) t TIME (ns) 1000 500 400 ny w o 6 6 8 ay oo pw 56 Oo 10 t A 4 Va POWER SWITCH [Oo Tog = LOLS ope Toy = 40KS ~ Note: No Diode Reverse or Forward Recovery Spike (See note 4.)! Diode Forward Characteristics 5 Vzsion) ~~ DIODE FORWARD VOLTAGE (V) 1 15 2 Fall Time As measured in the shown in Figure V,, = 25V Vour = SV 1 1, = 30mA T, = 25C 3 4 5 678910 |, OUTPUT CURRENT (A) Figure 2. P!C625, 626, 627 Switching Waveforms Note: PIC635, PIC636, PIC637 Circuit and waveforms are identical but of opposite polarity (V,, = 25Y, Vou = 5Vs Ipaive = +30mA.) 25 20 PRINTEO IN U.S.A.