EVAL6730 STMicroelectronics, EVAL6730 Datasheet - Page 33

• Manufacturer Part Number: EVAL6730
• Description: EVAL BOARD FOR L6730XX
• Manufacturer: STMicroelectronics
• Type: Motor / Motion Controllers & Driversr

Specifications of EVAL6730

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Power - Output: 66W
• Voltage - Output: 3.3V
• Current - Output: 20A
• Voltage - Input: 4.5 ~ 14V
• Regulator Topology: Buck
• Frequency - Switching: 400kHz
• Board Type: Fully Populated
• Utilized Ic / Part: L6730
• Input Voltage: 8 V to 52 V
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: L6208
• Other names: 497-5501

L6730 - L6730B
6
6.1
Application details
Inductor design
The inductance value is defined by a compromise between the transient response time, the
efficiency, the cost and the size. The inductor has to be calculated to maintain the ripple
current (ΔI
can be calculated with the following relationship:
Where F
voltage.
inductor, with V
Increasing the value of the inductance reduces the current ripple but, at the same time,
increases the converter response time to a load transient. If the compensation network is
well designed, during a load transient the device is able to set the duty cycle to 100% or to
0%. When one of these conditions is reached, the response time is limited by the time
required to change the inductor current. During this time the output current is supplied by
the output capacitors. Minimizing the response time can minimize the output capacitor size.
Figure 28. Inductor current ripple
Figure 28
SW
L
8
7
6
5
4
3
2
1
0
) between 20% and 30% of the maximum output current. The inductance value
is the switching frequency, V
0
IN
= 5 V and V
shows the ripple current vs. the output voltage for different values of the
1
O UT P UT V O L T AG E (V )
IN
Doc ID 11938 Rev 3
L
= 12 V at a switching frequency of 400 kHz.
≅
Vin
Fsw
2
−
IN
Δ ⋅
Vout
is the input voltage and V
I
L
⋅
Vout
Vin
3
(6)
4
Vin=5V, L=500nH
OUT
Vin=12V, L=1uH
Vin=5V, L=1.5uH
Vin=12V, L=2uH
Application details
is the output
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