Datasheet LTC3707-SYNC (Analog Devices) - 9
| 制造商 | Analog Devices |
| 描述 | High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator |
| 页数 / 页 | 32 / 9 — FUCTIONAL DIAGRAM. Figure 2. OPERATION (Refer to Functional Diagram). … |
| 文件格式/大小 | PDF / 404 Kb |
| 文件语言 | 英语 |
FUCTIONAL DIAGRAM. Figure 2. OPERATION (Refer to Functional Diagram). Main Control Loop
该数据表的模型线
文件文字版本
LTC3707-SYNC
FUCTIONAL DIAGRAM
PLLIN INTVCC VIN FIN PHASE DET D DUPLICATE FOR SECOND B 50k BOOST CONTROLLER CHANNEL PLLFLTR TG CB CLK1 DROP TOP + RLP OUT CIN OSCILLATOR D CLK2 1 C DET BOT FCB LP SW – 0.86V TOP ON S Q + SWITCH INTVCC V R Q OSENSE1 LOGIC PGOOD BG – BOT + 0.74V C PGND OUT+ B – 0.86V 0.55V + VOUT + – SHDN RSENSE VOSENSE2 – INTV + CC V 0.74V I1 I2 SEC 3V + – 4.5V – – + + – + 0.18μA BINH – + SENSE+ D 30k SEC C + SEC R6 FCB 3mV 0.86V + 4(VFB) SENSE– 30k FCB R5 – SLOPE COMP 45k 45k 3.3V 2.4V OUT 0.8V VOSENSE R2 + VREF VFB – – EA + 0.80V R1 VIN OV + VIN – 0.86V 4.8V + C I C 5V TH 1.2μA EXTV – CC LDO REG SHDN RUN C R RST SOFT C2 C INTVCC 6V 4(VFB) START 5V + RUN/SS SGND INTERNAL SUPPLY CSS 3707 FD/F02
Figure 2 OPERATION (Refer to Functional Diagram) Main Control Loop
by the EA. When the load current increases, it causes a slight decrease in V The IC uses a constant frequency, current mode step-down OSENSE relative to the 0.8V reference, which in turn causes the I architecture with the two controller channels operating TH voltage to increase until the average inductor current matches the new load current. 180 degrees out of phase. During normal operation, each After the top MOSFET has turned off, the bottom MOSFET top MOSFET is turned on when the clock for that channel is turned on until either the inductor current starts to sets the RS latch, and turned off when the main current reverse, as indicated by current comparator I2, or the comparator, I1, resets the RS latch. The peak inductor beginning of the next cycle. current at which I1 resets the RS latch is controlled by the voltage on the ITH pin, which is the output of each error The top MOSFET drivers are biased from fl oating bootstrap amplifi er EA. The VOSENSE pin receives the voltage feedback capacitor CB, which normally is recharged during each off signal, which is compared to the internal reference voltage cycle through an external diode when the top MOSFET 3707sfa 9
FUCTIONAL DIAGRAM
PLLIN INTVCC VIN FIN PHASE DET D DUPLICATE FOR SECOND B 50k BOOST CONTROLLER CHANNEL PLLFLTR TG CB CLK1 DROP TOP + RLP OUT CIN OSCILLATOR D CLK2 1 C DET BOT FCB LP SW – 0.86V TOP ON S Q + SWITCH INTVCC V R Q OSENSE1 LOGIC PGOOD BG – BOT + 0.74V C PGND OUT+ B – 0.86V 0.55V + VOUT + – SHDN RSENSE VOSENSE2 – INTV + CC V 0.74V I1 I2 SEC 3V + – 4.5V – – + + – + 0.18μA BINH – + SENSE+ D 30k SEC C + SEC R6 FCB 3mV 0.86V + 4(VFB) SENSE– 30k FCB R5 – SLOPE COMP 45k 45k 3.3V 2.4V OUT 0.8V VOSENSE R2 + VREF VFB – – EA + 0.80V R1 VIN OV + VIN – 0.86V 4.8V + C I C 5V TH 1.2μA EXTV – CC LDO REG SHDN RUN C R RST SOFT C2 C INTVCC 6V 4(VFB) START 5V + RUN/SS SGND INTERNAL SUPPLY CSS 3707 FD/F02
Figure 2 OPERATION (Refer to Functional Diagram) Main Control Loop
by the EA. When the load current increases, it causes a slight decrease in V The IC uses a constant frequency, current mode step-down OSENSE relative to the 0.8V reference, which in turn causes the I architecture with the two controller channels operating TH voltage to increase until the average inductor current matches the new load current. 180 degrees out of phase. During normal operation, each After the top MOSFET has turned off, the bottom MOSFET top MOSFET is turned on when the clock for that channel is turned on until either the inductor current starts to sets the RS latch, and turned off when the main current reverse, as indicated by current comparator I2, or the comparator, I1, resets the RS latch. The peak inductor beginning of the next cycle. current at which I1 resets the RS latch is controlled by the voltage on the ITH pin, which is the output of each error The top MOSFET drivers are biased from fl oating bootstrap amplifi er EA. The VOSENSE pin receives the voltage feedback capacitor CB, which normally is recharged during each off signal, which is compared to the internal reference voltage cycle through an external diode when the top MOSFET 3707sfa 9