MC34062

MC34062 MOTOROLA | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 11

Technical content

MOTOROLA SC {TELECON} OF D fp b367253 OOrseoo Oo

6367253 MOTOROLA SC (TELECOM) = OTE 79200

“ee 7 T-e2-// Advance Information ’ PIN-PROGRAMMABLE _& PIN-PROGRAMMABLE OVERVOLTAGE “CROWBAR” OVERVOLTAGE SENSING CIRCUIT SENSING CIRCUIT ‘The MC34062/35062 overvoltage protection (OVP) circuits require only an external “crowbar” SCR to protect sensitive electronic cir- SILICON MONOLITHIC cuitry from overvoltage damage. They sense an overvoltage condi- INTEGRATED CIRCUIT tion and quickly “crowbar”, or short circuit, the supply. An on-chip, tapped resistor network allows the device to be programmed for trip voltages ranging from 3.5 to 40 V. Each of the five programming pins provides one standard overvoltage trip point for nominal power supply voltages of 5.0, 12, 15, 24 or 28 V. Many other trip voltages may be programmed by interconnecting and grounding various com: P1 SUFFIX binations of these programming pins. Tables are provided in the PLASTIC PACKAGE Applications Information which show connection schemes for 120 CASE 626-08 trip voltages. ‘These circuits provide a cost-effective means of protecting either (MC34062 only) positive or negative power supplies. In addition, an external capa- citor may be used to program a minimum over voltage duration before tripping, thus providing noise immunity. The unique design of the ‘yy MC34062/35062 eliminates voltage and temperature drift errors Op A ' due to SCR gate variations. & I ‘OD 1 @ Unique Pin-Programmable Trip Voltage from 3.5 to 40 V 4, @ One-Pin Programming for 5.0, 12, 15, 24 and 28 V Power Supplies Y py © SCR Gate Drive Output of 200 mA "Sy © Built-In Hysteresis Voltage Ney © Wide Supply Range: 4.0V< Vcc < 40V wore AG vec 2 [8] Pins 4 thru ive Outpur 8 are used Drive Output [2] 2] to program FUNCTIONAL BLOCK DIAGRAM. Sense [3] [8] the Trip Voltage, | nn! a [8] Ver j H rip ° Top View i 13 vee (Top View) { Viet H ' 28V | t | U SUFFIX, 3 1 1 ‘CASE 693-02 i 2.96 oO 1 Drive 40 16 output | $60x nn aaa 1 is 50 i 8 H | [Nominal 1 . | 3272k 1 | Power | Ground | Typical 60 {| supply] Pin | Tein H 1 | Voltage | Number | Voltage | 30246 i [sov~t 4 | sav ° ! 12V 5 | 137Vv 70 ray} 8 fairy ORDERING INFORMATION | $368k | | av] oz | azav Temperature : H 1 | 2ev | 28 | arev |__Range Package so | 8510 125°6 | Ceramic OF t | mcssoszer | Pins 4 through 8 are used to program the Trip Voltage, Virip | cerame oi | ‘hua document conta inlormaton ana new product Spectiaons andvalarmaton Reve are subjec o change wahou nouce MOTOROLA LINEAR/INTERFACE DEVICES 3-216

MOTOROLA SC {TELECOM} O1 D pb3e7es3 gn79201 2 I 6367253 MOTOROLA SC (TELECOM) O1E 79201 DT-Ga-ll . Mc34062, MC35062 MAXIMUM RATINGS ° | Operating Voltage Vec-Vory | 40 | ver | Voltage Across Any internal Resistorin Network | Van | 40-+| veo _| | Current Through Any Resistor In Network [tan | 10 | ma_| | [-Sensevoioge Gene | 4 | vee | | Limited ‘Operating Ambiant Temperature 7 ‘acs40e2 010170 Mossos2 S125 Storage Terporaure Range eee near] -e | | ELECTRICAL CHARACTERISTICS (Vcc = 5.0 V: Vopv =0 V: Ta = Tow to Thigh unless otherwise specified.) [characteristic Symbol Min [tye [Max [unit | nT ‘Sense Trip Voltage VSense vide Tan zee 22 2575 Tiow to Thigh 2375 2625 Line Regulation. Vsense (3.0 V < Vcc - Vorv < 40-V) %/V Ta= 25°C oor | oot Tow '0 Thigh ooot_| doz Trip Voltage (Pin 4 = Gnd; Vpay=0 Vi Veeipt4) v Tas 250 oor Tiow t© Thigh 5.89 Fysteresis Voltage Pin 4 = God Vonv= OV) Vinay [eer [|v Trip Voltage {Pin § = Gnd;-Vpry = 0 V) v Tas 25°C 137 Tow Thigh 137 Hysteresis Voltage (Pin 5 = Gnd Vpav=0V) vas | — | 137 | - | v4 Trip Voltage (Pin 6 = Gnd; Vpry = 0 V) Varip(6) . Tas 26°C ws | aa | 16 Trow to Thigh 16.2 TAI 18.0 Trip Votoge (Pin 7 = Gd: ny = OV) Veit v Ta 20°C aes | 274 | 282 Tiow t0 Thigh 26.0 274 28.8 Trip Voltage (Pin 8 = Grd Von = OV) Vero) Tac 280 308 Tow Thigh 308 Traeteia Votage Pin = Gad: Vpay= OWI Vay | — |_| [v_] Tealir Network Current at Nominal Power Supply Valiago os Woo" 28. Vonv=0VPin 8 Gnd Drive Output Current, ON State. Tye 260c 130 Tost Thigh 80 Voc" 50 Vpav=0V os 38Ve voc vonve 40V os Drive Output Vg Transient Rejection ToRvirens Veo OV 1016 Vet dvedt= 200 V/s: Vorv = 0 V; Vgense = 0V: Ta= 26°C Tron 55°C for MC35062 Tigh = "125°C for MC3E082 Tone tr nteaeoee roc teemeawoen eS MOTOROLA LINEAR/INTERFACE DEVICES . 3-217

MOTOROLA SC {TELECOM} on p P3253 O079203 b

8367283 MOTOROLA SC (TELECOM) 00 O1E 79203 BD T-aal)

MC34062, MC35062 FIGURE 6 — DELAY CAPACITANCE versus DELAY TIME FIGURE 7 — DELAY CAPACITANCE versus DELAY TIME é FOR NOMINAL 6.0 V POWER SUPPLY FOR NOMINAL 12 V POWER SUPPLY . De ear iie eee meee etree sees 1 a re 4 HBR mRECRipeacsnie cent EE Het =a er < FREE IErthea SSSR Smee tiene apainiaeeeey | 3 10 EEE tice He $0 SECO a Fe Se eeeii camee Gemee emer ae Beet ae = ofa SECTS = 2 on CCT Tee er ee ee ahs} lela oie Ser] 5 BEER REE H HE i | aie aeol! apace ma oo HEHE EE He Hono EEESSERH HEPA PE ‘uot oot a is 10 200 oa ay to ‘0 ‘py. DELAY TIME (ms) ‘tory, DELAY TIME (ms) FIGURE 8 — DELAY CAPACITANCE versus DELAY TIME FIGURE 9 — DELAY CAPACITANCE versus DELAY TIME, FOR NOMINAL 16 V POWER SUPPLY FOR NOMINAL 24 V POWER SUPPLY 10 epee rte rr 10 pepe ra eay = GEERT eas Cg ER ae

3 GEE Tac Oar 3 10 SEE a

§ GRC SSH eae Eth §=© EEE HEH Ee eee eit Soo ee ga Les ea fo eceeee ae eet] So Cee Sas 4 esos seme eee 1 ameei anmetil mea rt oon HH Here oot HET eH HEHE 000 00 ar io ‘0 001 oot a io ‘0 ‘pLy. DELAY TIME (ms) ‘toy. DELAY TIME (ms) FIGURE 10 — DELAY CAPACITANCE vorsus DELAY TIME FOR NOMINAL 28 V POWER SUPPLY

3 GLEE TEESE rca

8 EES a

§ oo GEER err ’ : EMU SeSeriic eet cee can % 001 baletal Uae CITT sear 2 , & Fe soe ce ve | Sc aeenihSoZeeeett ee ooo ACE HHT HE 0.00 oot On 19 10 ‘tpyy, DELAY TIME ims) MOTOROLA LINEAR/INTERFACE DEVICES 3-219

MOTOROLA SC {TELECOM} OL D B367253 DOvI2O4 6 OT 6367253 MOTOROLA SC CTELECOM) O1E 79204 D 8-1) . Mc34062, MC35062 ; APPLICATIONS INFORMATION BASIC CIRCUIT CONFIGURATION By making the proper choice of Ry and R2, 8 level The MC34062 and MC35062 each consist of a 2.5 V detector for any voltage from 3.5 to 40 V may be shunt reference, a comparator with built-in hysteresis, realized, = = 8 power output transistor, and an on-chip, tapped resistor . mre on-chip rer Bloc cowork lad configured as shows Es foc R2 through 8) provides one standard overvoltage trip point 299 at the inverting input of the comparator is Rie rg for nominal power supply voltages of 5.0, 12, 18, 24 or 28 V. These standard trip points are implemented by . while the voltage at the non-inverting inputis V¢¢-2.5 V. grounding one of the five programming pins, and are Thus, for a given (Ry, R2) voltage divider, the compara- summarized in the following table: tor's output state is a function of Vcc. The following table applies: Nominal Power Ground | Typical Supply Pin Trip Voltage Number | Voltage 5.0V 4 6.2V <BaA80| ore su | 12v 8 | sav! 1 15V 6 ARG | Ry +R: 24v 7 274V FIGURE 11 ~ BLOCK DIAGRAM AND TYPICAL APPLICATION w+, Vout r 1 t T O1 \\ 1 Yee i Veet i i 25V ! Sense | I * S [| | rove oF | Sut ' a - i ® 1 ome if. | oun - ot 2 Oo rs meng Verip= 282 25 4 three ‘trip Ry ° Programming Pins Gnd Many other trip voltages may be programmed by Some precautions are necessary in the operation of the interconnecting and grounding various combinations Protection circuit shown in Figure 11. Note that even in of the programming pins. Table 1 provides connection the OFF State, a minimum drive output current, equal to schemes for 120 nominal Trip Voltages (Vrrip)- the sum of the reference and comparator supply currents, Additional Trip Voltages may also be implemented with is available. Therefore, a means of ‘shunting this current other pin connections. All of these Trip Voltages will be away from the driven circuit is necessary. In the example within +3.0% of the nominal value at Ta = 25°C andwith- of Figure 11; 2 100 0 resistor (RGK) is used, producing in +5.0% over the operating temperature range. voltage at the Drive Output of approximately 60 mV in the The hysteresis built into the comparator is 250 mV at OFF State. the inverting input. This comparator hysteresis. voltage is In the ON State the MC34062 becomes a current source Ry +R2 capable of saturating to within 2.0 V of Vcc. Therefore, multiplied by the ratio ——, just as the 2.6 V Sense’ Trip when driving a high impedance load, it may be desirable Ry to clamp the drive output to at least 3.0 V below Vcc Voltage (VSense) is multiplied by the same ratio to detine (Vec - Vorv = 3.0 V) if it is important that the reference tho Trip Voltage (Virip). Thus, the Hystoresis Voltage(V})is continue to regulate. approximately 10% of the Trip Voltage foranyTrip Voltage. eee MOTOROLA LINEAR/INTERFACE DEVICES 3-220

. 6367253 0 MOTOROLA SC {TELECON} oO. D Ml ors20s 0 6367253 MOTOROLA SC (TELECOM) ~~ O1E 79205. .b Toa. »] MC34062, MC35062 PROGRAMMING A MINIMUM OVERVOLTAGE Figures 6 through 10 show the Coy values versus DURATION BEFORE TRIPPING: delay time (tpLy) for nominal 5.0, 12, 15, 24 and 28 V Atime delay may be programmed into the operation of power supply protection circuits, each using a one-pin the MC34062/35062 to provide noise immunity. This MC34062/35062 programming scheme. These figures time delay is implemented by adding a capacitor (CpLy) also show the change in ty with variations in the over- between the Vcc and Sense leads as shown in Figure 12. voltaged supply. Voc. The time delay obtained by this technique is a function of the internal resistors (Ry, R2) and CpLy. as well as the THE NEED FOR A GATE RESISTOR nominal supply voltage, VCC(nom). 8nd the overvoltaged For power supplies above 11 V, a gate resistor, RG, in supply voltage Vcc. The nominal supply voltage deter- series with the SCR gate is recommended to limit the mines the initial charge on Cpcy, while the magnitude of power dissipated by the IC to approximately 2.0 W. This the overvoltage condition determines the rate at which resistor will protect the MC34062/35062 in the event CDLy charges to the reference voltage, Vref = 2.6 V. Thus, of a defective or missing SCR, while allowing the maxi- for a given Ry, Rz and Cy, the time delay is reduced as mum drive output current to the gate of the SCR. Figure 5 the overvoltage is increased. The expression for the time shows the minimum recommended gate resistor. RG{min}- delay, toy is: versus the power supply voltage, Vcc. A larger value of RG may be used if less drive current is needed. _ *1R2 Cory Vcc - Vecinom) Ry +R Vcc - Virip here: Virip = 212.5.) where: Virip = 2. FIGURE 12 — OVERVOLTAGE PROTECTION WITH TIME DELAY O Pos 4 ° : [weve | ? + 2 Rg Power 4thrus8 ety © Programming Pins Rok Gnd fe) MOTOROLA LINEAR/INTERFACE DEVICES 3-221

MOTOROLA SC {TELECOM} 02 ff b367253 co79206 1 | “6367253 WOTOROLA SE (TELECOM) “OIE 79208 oT wan) | ~ Mc34o62,Mc35062 OC | TABLE 1 — PIN-PROGRAMMING OF RESISTOR NETWORK FOR NOMINAL TRIP VOLTAGES [vm [ma] oe [re] me [maf oe [ove [ me Pe [me me [oe] ees pom eter fo fe fels feel tel Pols | | pee [ete f fel | los [ ete ler ray | pow | efor [ye Poel Ty foo [tet] Ty [| fw eters Tete ls om [ete fea yy || pm et [effets fe [ tetera | foe] efeef ols fof em felel TT Ty | pm [ efets | fs [ole [et fe Pf | a ——} tj} few] et Totes fom fel ty fmf | | jew | efor} Poly [oem [ete fol aT | ad eee ee ee fertete tats fof ef et TT ely pew} etetels | [olen | ele l thy paps | Re Ce em [ef eta Tels Polo a fete |] ad ee a jew | efee[ epee rm] | lefty jew | pf fo fol fowl om | fora [ml Ty ERS Recoc Sy ee MOTOROLA LINEAR/INTERFACE DEVICES - 3-222 SE .

~~ woToROLA SC <TELEcons on > 6367253 0079207 3 T eine

6367253 MOTOROLA SC CTECETOM yo 01E°79207 DT-Ga-1)

MC34062, MC35062 TABLE 1 — (Continued) [ioe [ome [ome [me [me] ve [ev [ree [re] ms [ve [rr | me nny ee Pliny enone few [ Pelete fe | leet Pet tts [| fmf [elets | [eie| Petet ts | | fmf [eteeterts [mmm | [otete| Ts | fe[ [elets| [ yee[ [et tele |_| fem fet tel y fone [ets | etels || Denno oer [em [el eterterte Ps [om [ets | ote tel | fom era [om foo] et Peel | ee] fom f Petal [els fmf [ef tet ts | . Pew [el eee [mf | ets [tele | Pe febels fe { [fem [ [ets [tele | Dnnboe oneene oe a ae noe eee fe ( Pets fef | dee? | fet | | fem | fet feta ls om | fe | | fee} [et feds fmm | ets | ot Ls | | er fets te [| jem] | Tebets || a MOTOROLA LINEAR/INTERFACE DEVICES . 3-223

MOTOROLA SC {TELECOM} O DP) b3b7253 oo7s208 s

6367253 MOTOROLA SC (TELECOM) ~~~""“o1e 79208 “Dba -

---""Micaaoe2, Mc35062,—O TABLE 1 — (Continued) ed ee “= SRenoney fem [ef [ly [ow | ee ee i CoRrcorsee 1 jt | Se eee ee ee ee |_| J | pew lets | [ett s feel Pets | f feo| em] [Pete tel Ym fete tele | fon pe} | pow] [fet feels fae PT Tom fey | ref ff fel Teme tele fey | wee ee | ee ec bw] ety] [else leel ets] [f= ee | th — fee ef et To em feels | ml | SN oor |_| eo fem{ ets [ets fl mel ff fT fe Jeet et Pe] | [elem ebele ls] fa |__| a ee oe Sm oer fem [ote [sl [ dom eels | [fe] MOTOROLA LINEAR/INTERFACE DEVICES (3-224 A

MOTOROLA SC {TELECON} O1 D ff L347253 covs203 7 § ~~ 6367253 MOTOROLA SC (TELECOM) O1E 79209 D-Tha-ll . MC34062, MC35062 CROWBAR SCR CONSIDERATIONS ‘Since the anode current flows through this turned-on . gate region, very high current densities can occur in Referring to Figure 13, it canbe seen that the crowbar the gate rogion if high anode currents appear quickly SCR, when activated, is subject to a large current surge (di/dt). This can result in immediate destruction of from the output capacitance, Coyt. This capacitance the SCR or gradual degradation of its forward blocking * consists of the power supply output capacitors, the load’s voltage capabilities — depending on the severity of the decoupling capacitors, and in the case of Figure 13A, the ‘occasion. supply’s input filter capacitors. This surge current isillus- q / ‘ The value of di/dt that an SCR can safely handle is trated in Figure 14, and can cause SCR failure or dagra- influenced by its construction and the characteristics dation by any one of three mechanisms: di/dt, absolute of the gate drive signal. A center-gate-fire SCR has peak surge. or !2t. The interrelationship of these failure snore divdt capability than a corner-yate-fire type, and methods and the breadth of the applications make speci- hesvily overdriving (2 to 6 times ter! the SCR gate fication of the SCR by the semiconductor manufacturer with a fast <1.0 us rise time signal will maximize its difficult and expensive. Therefore, tha designer must di/dt capability. A typical maximum number in phase empirically determine the SCR and circuit elements control SCRs of less than 50 A(RMS) rating might be which result in reliable and effective OVP operation. 200 A/yus, assuming a gate current of five times IGT However, an understanding of the factors which influence and<10nsrise time. I having done this, a di/dt prob- the SCR’s di/dt and surge capabilities simplifies this task, lemis seen to still exist, thedasigner canaleodecrease 1. di/dt the di/dt of the current waveform by adding induc- . tance in series with the SCR, as shown in Figure 15. As the gate region of the SCR is driven on, its area Of course, this reduces the circuit's ability to rapidly of conduction takes a finite amount of time to grow, reduce the dc bus voltage and a tradeoff must be made starting as a very small region and gradually spreading. between speedy voltage reduction and di/dt. FIGURE 13 — TYPICAL CROWBAR CIRCUIT ‘CONFIGURATIONS 143A — SCR ACROSS INPUT OF REGULATOR ‘ i Series | ij 13B — SCR ACROSS OUTPUT OF REGULATOR °

7 Seri >

*Needad if supply not current timited MOTOROLA LINEAR/INTERFACE DEVICES 3-225