Datasheet LTC3613 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | 24V, 15A Monolithic Step Down Regulator with Differential Output Sensing |
| Pages / Page | 36 / 10 — FUNCTIONAL DIAGRAM. OPERATION (Refer to Functional Diagram). Main Control … |
| File Format / Size | PDF / 464 Kb |
| Document Language | English |
FUNCTIONAL DIAGRAM. OPERATION (Refer to Functional Diagram). Main Control Loop
Model Line for this Datasheet
Text Version of Document
LTC3613
FUNCTIONAL DIAGRAM
VIN CIN PV SV IN IN INPUT SUPPLY IN CIN LDO OUT EN BO0ST UVLO D + B – 3.65V TG DRV MT C 4.2V B – R SW L SENSE VOUT EXTV 1.3μA CC + RUN + 0.75V 4.6V – – C 1.2V – START OUT LOGIC INTVCC CONTROL INTVCC VOUT ONE-SHOT STOP R TIMER FB2 CVCC BG DRV MB TIME RFB1 ADJUST PGND ICMP IREV – + – + CLOCK MODE/PLLIN CLOCK PLL DETECT SYSTEM SENSE+ SENSE– RT OSCILLATOR 1μA RT TRACK/SS + C + SS 0.6V INTVCC V + OSNS + 0.645V – + RPGD PGOOD OV EA DA – (g (A = 1) – m(EA) = 1.7mS) V – OSNS 3613 FD + UV– 0.555V VRNG ITH SGND INTVCC RITH R1 CITH1 R2
OPERATION (Refer to Functional Diagram) Main Control Loop
In normal steady-state operation, the top MOSFET is turned on for a fixed time interval proportional to the delay in the The LTC3613 uses valley current mode control to regulate one-shot timer. The PLL system adjusts the delay in the the output voltage in a monolithic, all N-channel MOSFET one-shot timer until the top MOSFET turn-on is synchro- DC/DC step-down converter. Current control is achieved by nized either to the internal oscillator or the external clock sensing the inductor current across SENSE+ and SENSE–, input if provided. As the top MOSFET turns off, the bottom either by using an explicit resistor connected in series with MOSFET turns on with a small time delay (dead time) to the inductor or by implicitly sensing the inductor’s resis- avoid shoot-through current. The next switching cycle is tive (DCR) voltage drop through an RC filter connected initiated when the current comparator, I across the inductor. CMP, senses that inductor current has reached the valley threshold point 3613fa 10
FUNCTIONAL DIAGRAM
VIN CIN PV SV IN IN INPUT SUPPLY IN CIN LDO OUT EN BO0ST UVLO D + B – 3.65V TG DRV MT C 4.2V B – R SW L SENSE VOUT EXTV 1.3μA CC + RUN + 0.75V 4.6V – – C 1.2V – START OUT LOGIC INTVCC CONTROL INTVCC VOUT ONE-SHOT STOP R TIMER FB2 CVCC BG DRV MB TIME RFB1 ADJUST PGND ICMP IREV – + – + CLOCK MODE/PLLIN CLOCK PLL DETECT SYSTEM SENSE+ SENSE– RT OSCILLATOR 1μA RT TRACK/SS + C + SS 0.6V INTVCC V + OSNS + 0.645V – + RPGD PGOOD OV EA DA – (g (A = 1) – m(EA) = 1.7mS) V – OSNS 3613 FD + UV– 0.555V VRNG ITH SGND INTVCC RITH R1 CITH1 R2
OPERATION (Refer to Functional Diagram) Main Control Loop
In normal steady-state operation, the top MOSFET is turned on for a fixed time interval proportional to the delay in the The LTC3613 uses valley current mode control to regulate one-shot timer. The PLL system adjusts the delay in the the output voltage in a monolithic, all N-channel MOSFET one-shot timer until the top MOSFET turn-on is synchro- DC/DC step-down converter. Current control is achieved by nized either to the internal oscillator or the external clock sensing the inductor current across SENSE+ and SENSE–, input if provided. As the top MOSFET turns off, the bottom either by using an explicit resistor connected in series with MOSFET turns on with a small time delay (dead time) to the inductor or by implicitly sensing the inductor’s resis- avoid shoot-through current. The next switching cycle is tive (DCR) voltage drop through an RC filter connected initiated when the current comparator, I across the inductor. CMP, senses that inductor current has reached the valley threshold point 3613fa 10
