CS51311GDR14 Просмотр технического описания (PDF) - Cherry semiconductor

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CS51311GDR14

Synchronous CPU Buck Controller for 12V and 5V Applications

Cherry semiconductor 

Typical Performance Characteristics

Figure 1: Gate(H) and Gate(L) Falltime vs. Load Capacitance.

150

125

100

75

50

25

0

0

VCC = 12V

TA = 25°C

2000

4000 6000 8000 10000 12000 14000 16000

Load Capacitance (pF)

Figure 4: Percent Output Error vs. DAC Output

Voltage Setting, VID4 = 0.

0.10

0.05

0

−0.05

VCC = 12V

−0.10

TA = 25°C

−0.15

VID4 = 0

−0.20

1.325 1.375 1.425 1.475 1.525 1.575 1.625 1.675 1.725 1.775 1.825 1.875 1.925 1.975 2.025 2.075

DAC Output Voltage Setting (V)

Figure 2: Gate(H) and Gate(L) Risetime vs. Load Capacitance.

150

125

100

75

50

25

0

0

VCC = 12V

TA = 25°C

2000

4000 6000 8000 10000 12000 14000 16000

Load Capacitance (pF)

Figure 3: DAC Output Voltage vs. Temperature,

DAC Code = 00001.

0.10

0.05

VCC = 12V

0

−0.05

−0.10

−0.15

0

20

40

60

80

100

120

Junction Temperature (°C)

Figure 5: Percent Output Error vs. DAC Output

Voltage Setting, VID4 = 1.

0.35

0.30

0.25

0.20

0.15

0.10

0.05

0

−0.05

−0.10

VCC = 12V

−0.15

TA = 25°C

−0.20

VID4 = 1

−0.25

2.125 2.225 2.325 2.425 2.525 2.625 2.725 2.825 2.925 3.025 3.125 3.225 3.335 3.425 3.525

DAC Output Voltage Setting (V)

Application Information

Theory Of Operation

V2TM Control Method

PWM

Comparator

–

C

GATE(H)

GATE(L)

The V2TM method of control uses a ramp signal that is gen-

erated by the ESR of the output capacitors. This ramp is

proportional to the AC current through the main inductor

and is offset by the value of the DC output voltage. This

control scheme inherently compensates for variation in

either line or load conditions, since the ramp signal is gen-

erated from the output voltage itself. This control scheme

differs from traditional techniques such as voltage mode,

which generates an artificial ramp, and current mode,

which generates a ramp from inductor current.

The V2TM control method is illustrated in Figure 6. The out-

put voltage is used to generate both the error signal and

the ramp signal. Since the ramp signal is simply the output

Ramp Signal

COMP

Error

Amplifier –

E

Error

Signal

+

Figure 6: V2TM Control Diagram

6

Output

Voltage

Feedback

VFB

Reference

Voltage

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