ULQ2460A ALLEGRO

Document overview

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Technical content

The ULQ2460A, ULQ2460C, and ULQ2460LW electronic ignition ULQ2460A timing circuits are intended to interface between conventional electro- magnetic pick-ups, a computer-controlled electronic spark timing (EST) ecxur CA n » EE] picaur + computer, and a high-efficiency ignition coil. sas[2] OH In application, the devices are designed to withstand various load o Gt Piz] OweLL dump and battery supply transients and to protect their output. They ‘ROUND ‘CONTROL provide a positive shut down feature if battery supply voltages exceed surety [4] Yop € [a] estcompurea 35 V. In the event of an open or shorted signal input, they provide a oururt oh afi nerenence fail-safe mode that shuts off the output. if the EST computer fails or is WAVESHAPE disconnected, the ULQ2460A/C/LW will continue to process the pickup sense [6] 8 [9 ] sypass mope signal and thus allow the engine to continue to operate in a “limp” or POWER | no [pa] 8 Soft-failure mode. For additional reliability improvement, a constant- ‘GROUND! (COMECTION current ignition coil drive eliminates the need for the usual ballast resistor. Dwg, No, PS-018. ‘The ULQ2460A is furnished in a 14-pin dual in-line plastic pack- age. The ULQ2460LW is supplied in a surface-mountable 16-lead wide-body SOIC. The ULQ2460C is an unpackaged, passivated, chip for hybrid applications. All devices are rated for operation over the automotive/industrial temperature range of -40°C to +85°C.

FEATURES

ll Improved System Reliability ll internal Bypass Mode @ Constant-Current Drive to Ignition Coil @ 180 mJ Primary Coil Energy ABSOLUTE MAXIMUM RATINGS in Typical Application Package Power Dissipation, Po.eseeeeeeeeseses sees See Graph Operating Temperature Range, : Treeeceeeeereeee es “G0°C to 485°C Aways order by complete part number: Storage Temperature Range, Te esccvevsevsess 165°C to 4150°C re 5-11 @™ 0504336 0008174 154 mm

ELECTRONIC IGNITION TIMING FUNCTIONAL BLOCK DIAGRAM AND TYPICAL APPLICATIONS [4 BATTERY cor 22 a rn AONE NE omy ae ay hp IY <ime soa | POWER cs -+—Pp LD ' me nl H + + i we | 5.6 nF g: T § a = WAVESHIPE * wg. No. FS-011 £25 ULQ2460LW 5 20 pickup - [1|N P [16] pickup BIN . o

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ge NON enouno [i] wet an NIX surPLy [4 ] Veg € [13] est comPUTER 5 0s SUFFOCLW, Ray, 295M WN sense [6 } B [11] BYPASS MODE XQ 2 oS 50 75 400. 125 150 conneoTion LEghN® Ne 19) COnmEcTION (AMBIENT TEMPERATURE IN °C wo. Ne. 25.0008 wg Mo P8018 SY 5-12 mm 0504338 0008175 O70 a

ELECTRICAL CHARACTERISTICS at T, = +25°C, Voc = 16 V, in typical application (unless otherwise noted). [J timits eas a ee a Co a A [See Relive ————f [esteem ae Pa nn ee “ See EY ee eens R= ee [eaten Gon tee [Vannd¥ eo Threshold Voltage Temperature Coetticient Fe [ease [oe [emer fe Discharge Current NOTE: Pin numbers apply to ULQ2460A. Continued next page... ES 5-13 M@™® 0504338 0008176 Te?

ELECTRONIC IGNITION TIMING ELECTRICAL CHARACTERISTICS continued Pa Test Conditions [ in. typ. Max._| units _| reshold Con Advance Control Advance Control ee NOTE: Pin numbers apply to ULQ2460A. ULQ2460C -(Pad numbers apply to ULQ2460A) AIG ea | ars) ii bree MO Pel ele Bees a Ei ay ie ea ir 1, Pa a ‘il iio Eo e a 5-14 mm 0504338 0008177 963 a

Pe eaiwa lh a Te oats hog a SR ea aa ie rae ar re E2460” aie tion: SR a es ern a iene re TROMC GNITIO} UTE uf ING ee ee oe CIRCUIT DESCRIPTION & TYPICAL APPLICATION The ULQ2460A, ULQ2460C, or ULQ2460LW electronic ignition timing circuit is connected to the electronic spark timing computer at three points: REFERENCE WAVESHAPE (R). Sends engine crankshatt position and speed information to the electronic spark timing computer as determined by the state of the bypass control input. ELECTRONIC SPARK TIMING (E). Receives dwell and timing information from the electronic spark timing computer for the initiation of primary coil current and spark timing. When the EST computer is in control (input B pulled high), a constant-current sink at this input tums ON as confirmation back to the computer. BYPASS MODE (B). With an active-low signal from the electronic ‘spark timing computer or open circuit at this input (either is indicative of a computer failure), the device senses and processes the input signal received from the pickup coil, thereby generating and controlling dwell, spark timing, and spark advance without the aid of the computer (bypass mode). With a high signal input from the computer, the ULQ2460A/C/LW processes the input signal received from the pickup coil, generating a modified pulse train at the reference waveshape output which, after processing by the EST computer, is returned to the device through the EST terminal thereby allowing the computer to determine dwell, spark timing, and spark advance (EST mode). The floating, ground-isolated signal generated by the electromag- netic pick-up is connected to the circuit through the P (positive) and N (negative) inputs. The output of the circuit is connected through an external Darlington-connected power driver and the primary winding of a high- efficiency ignition coil to the battery without the need for ballast resistor protection and provides the following functions: 1. Stores energy in the magnetic field of the ignition coil based on the available dwell time. 2. Limits the maximum energy stored in the magnetic field of the ignition coil by limiting the maximum current that can be achieved (typically 5.5 A). 3. At the required time, it rapidly shuts off the coil current causing a collapse of the magnetic field and dumping the stored energy through the secondary winding at a very- high voltage into the spark plug. In the EST mode of operation, the output is totally under the control of the computer. rr 5-15 M@™ 0504338 0008178 aTT a