TL2843BQDRQ1

TL2843B-Q1 SLVSAE2A – JULY 2010 – REVISED FEBRUARY 2012 www.ti.com HIGH-PERFORMANCE CURRENT-MODE PWM CONTROLLER Check for Samples: TL2843B-Q1 FEATURES 1 • • • • • • • • • Qualified for Automotive Applications Low Start-Up Current ( 5 kΩ: f ≉ 1.72 / RTCT VREF RT RT/CT CT GND Figure 3. Oscillator Section 10 Submit Documentation Feedback Copyright © 2010–2012, Texas Instruments Incorporated Product Folder Link(s): TL2843B-Q1 TL2843B-Q1 SLVSAE2A – JULY 2010 – REVISED FEBRUARY 2012 www.ti.com TIMING RESISTANCE vs FREQUENCY DEAD TIME vs TIMING CAPACITANCE 100 100 CT = 10 nF VCC = 15 V RT ≥ 5 kΩ TA = 25°C 40 CT = 4.7 nF CT = 2.2 nF R T − Timing Resistance − k Ω Dead Time − µ s 40 10 4 1 CT = 1 nF CT = 22 nF 10 CT = 47 nF CT = 100 nF 4 0.4 VCC = 15 V TA = 25°C 1 100 0.1 1 4 10 40 100 1k 10k 100k 1M f − Frequency − Hz CT − Timing Capacitance − nF Open-Loop Laboratory Test Fixture In the open-loop laboratory test fixture (see Figure 4), high peak currents associated with loads necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to the GND terminal in a single-point ground. The transistor and 5-kΩ potentiometer sample the oscillator waveform and apply an adjustable ramp to the ISENSE terminal. REF RT A 4.7 kΩ VCC 2N2222 100 kΩ 1-kΩ Error Amplifier Adjust VFB 5 kΩ VREF COMP TL284xB TL384xB 0.1 µF VCC 0.1 µF ISENSE OUTPUT 1 kΩ, 1 W OUTPUT 4.7 kΩ ISENSE Adjust RT/CT GND GND CT Figure 4. Open-Loop Laboratory Test Fixture Submit Documentation Feedback Copyright © 2010–2012, Texas Instruments Incorporated Product Folder Link(s): TL2843B-Q1 11 TL2843B-Q1 SLVSAE2A – JULY 2010 – REVISED FEBRUARY 2012 www.ti.com Shutdown Technique The PWM controller (see Figure 5) can be shut down by two methods: either raise the voltage at ISENSE above 1 V or pull the COMP terminal below a voltage two diode drops above ground. Either method causes the output of the PWM comparator to be high (see the Functional Block Diagram). The PWM latch is reset dominant so that the output remains low until the next clock cycle after the shutdown condition at the COMP or ISENSE terminal is removed. In one example, an externally latched shutdown can be accomplished by adding an SCR that resets by cycling VCC below the lower UVLO threshold. At this point, the reference turns off, allowing the SCR to reset. 1 kΩ VREF COMP Shutdown 330 Ω ISENSE 500 Ω Shutdown To Current-Sense Resistor Figure 5. Shutdown Techniques A fraction of the oscillator ramp can be summed resistively with the current-sense signal to provide slope compensation for converters requiring duty cycles over 50% (see Figure 6). Note that capacitor C forms a filter with R2 to suppress the leading-edge switch spikes. VREF 0.1 µF RT RT/CT CT R1 ISENSE R2 ISENSE C RSENSE Figure 6. Slope Compensation 12 Submit Documentation Feedback Copyright © 2010–2012, Texas Instruments Incorporated Product Folder Link(s): TL2843B-Q1 TL2843B-Q1 SLVSAE2A – JULY 2010 – REVISED FEBRUARY 2012 www.ti.com REVISION HISTORY Changes from Original (July 2012) to Revision A Page • Changed the pinout from an 8-pin to 14-pin D package ....................................................................................................... 1 • Changed the Functional Block diagram pin numbers for the 14-pin D package .................................................................. 2 Submit Documentation Feedback Copyright © 2010–2012, Texas Instruments Incorporated Product Folder Link(s): TL2843B-Q1 13 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) (6) TL2843BQDRQ1 ACTIVE SOIC D 14 2500 RoHS & Green NIPDAU Level-1-260C-UNLIM -40 to 125 TL2843BQ (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of