Datasheet LT1070, LT1071 (Linear Technology) - 6
| Manufacturer | Linear Technology |
| Description | 5A and 2.5A High Efficiency Switching Regulators |
| Pages / Page | 12 / 6 — TYPICAL PERFORMANCE CHARACTERISTICS. Transconductance of Error. Switch … |
| Revision | E |
| File Format / Size | PDF / 218 Kb |
| Document Language | English |
TYPICAL PERFORMANCE CHARACTERISTICS. Transconductance of Error. Switch “Off” Characteristics. VC Pin Characteristics. Amplifier
Model Line for this Datasheet
Text Version of Document
LT1070/LT1071
W U TYPICAL PERFORMANCE CHARACTERISTICS Transconductance of Error Switch “Off” Characteristics VC Pin Characteristics Amplifier
1000 300 7000 – 30 TJ = 25°C 900 6000 200 θ 0 800 V 5000 30 µA) FB = 1.5V 700 100 µmho) µA) (CURRENT INTO V 4000 gm 60 PHASE ( 600 C PIN) 0 500 3000 90 VSUPPLY = ° –100 ) 400 VFB = 0.8V 2000 120 PIN CURRENT ( (CURRENT OUT OF VC PIN) 300 3V 15V 40V 55V C SWITCH CURRENT ( V – 200 1000 150 200 TRANSCONDUCTANCE ( – 300 0 180 100 0 – 400 –1000 210 0 10 20 30 40 50 60 70 80 90 100 0 0.5 1.0 1.5 2.0 2.5 1k 10k 100k 1M 10M SWITCH VOLTAGE (V) V FREQUENCY (Hz) C PIN VOLTAGE (V) 1070/71 G19 1070/71 G21 1070/71 G20
W BLOCK DIAGRAM
16V SWITCH VIN OUT 2.3V FLYBACK REG ERROR AMP 40kHz LOGIC DRIVER 5A, 75V OSC SWITCH MODE ANTISAT SELECT COMP – FB ERROR VC + AMP + SHUTDOWN CURRENT 0.02Ω CIRCUIT AMP (0.04Ω LT1071) 1.24V – GAIN ≈ 6 REF 0.15V 1070/71 BD
U OPERATION
The LT1070/LT1071 is a current mode switcher. This voltage is obtained by using the output of a voltage means that switch duty cycle is directly controlled by sensing error amplifier to set current trip level. This switch current rather than by output voltage. Referring to technique has several advantages. First, it has immediate the Block Diagram, the switch is turned “on” at the start response to input voltage variations, unlike ordinary of each oscillator cycle. It is turned “off” when switch switchers which have notoriously poor line transient current reaches a predetermined level. Control of output response. Second, it reduces the 90° phase shift at 10701fe 6
W U TYPICAL PERFORMANCE CHARACTERISTICS Transconductance of Error Switch “Off” Characteristics VC Pin Characteristics Amplifier
1000 300 7000 – 30 TJ = 25°C 900 6000 200 θ 0 800 V 5000 30 µA) FB = 1.5V 700 100 µmho) µA) (CURRENT INTO V 4000 gm 60 PHASE ( 600 C PIN) 0 500 3000 90 VSUPPLY = ° –100 ) 400 VFB = 0.8V 2000 120 PIN CURRENT ( (CURRENT OUT OF VC PIN) 300 3V 15V 40V 55V C SWITCH CURRENT ( V – 200 1000 150 200 TRANSCONDUCTANCE ( – 300 0 180 100 0 – 400 –1000 210 0 10 20 30 40 50 60 70 80 90 100 0 0.5 1.0 1.5 2.0 2.5 1k 10k 100k 1M 10M SWITCH VOLTAGE (V) V FREQUENCY (Hz) C PIN VOLTAGE (V) 1070/71 G19 1070/71 G21 1070/71 G20
W BLOCK DIAGRAM
16V SWITCH VIN OUT 2.3V FLYBACK REG ERROR AMP 40kHz LOGIC DRIVER 5A, 75V OSC SWITCH MODE ANTISAT SELECT COMP – FB ERROR VC + AMP + SHUTDOWN CURRENT 0.02Ω CIRCUIT AMP (0.04Ω LT1071) 1.24V – GAIN ≈ 6 REF 0.15V 1070/71 BD
U OPERATION
The LT1070/LT1071 is a current mode switcher. This voltage is obtained by using the output of a voltage means that switch duty cycle is directly controlled by sensing error amplifier to set current trip level. This switch current rather than by output voltage. Referring to technique has several advantages. First, it has immediate the Block Diagram, the switch is turned “on” at the start response to input voltage variations, unlike ordinary of each oscillator cycle. It is turned “off” when switch switchers which have notoriously poor line transient current reaches a predetermined level. Control of output response. Second, it reduces the 90° phase shift at 10701fe 6
