EVAL6730 STMicroelectronics, EVAL6730 Datasheet - Page 14

• 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

AN1451 APPLICATION NOTE
Figure 13. Output Current Regulation Waveforms
Figure 14 shows the magnitude of the Off Time t
culated from the equations:
where R
Therefore:
These values allow a sufficient range of t
The capacitor value chosen for C
The Rise Time t
monostable is triggered. Therefore, the on time t
be bigger than t
14/43
R
V
V
SENSE
I
SENSE
OUT
V
REF
2.5V
OFF
V
ON
5V
t
t
20K
0.47nF
t
t
t
REF
0
RC
RCFALL
OFF
DT
OFF(MIN)
OFF(MAX)
OFF
= 1µs (typical value)
= t
SYNCHRONOUS OR QUASI
SYNCHRONOUS RECTIFICATION
and C
D01IN1334
RCFALL
= 0.6 · R
R
= 6.6µs
C
RCRISE
OFF
= 6ms
RCRISE
OFF
OFF
+ t
100K
OFF
are the external component values and t
for allowing a good current regulation by the PWM stage. Furthermore, the on time t
100nF
will only be an issue if the capacitor is not completely charged before the next time the
DT
= 0.6 · R
· C
OFF
OFF
OFF
also affects the Rise Time t
· C
OFF
OFF
B
to implement the drive circuit for most motors.
Slow Decay
+ t
OFF
t
RCFALL
ON
DT
1 s t
1 s t
t
t
RCRISE
OFF
versus C
, which depends by motors and supply parameters, has to
C
BLANK
DT
OFF
D
DT
RCRISE
and R
is the internally generated Dead Time with:
t
ON
A
OFF
of the voltage at the pin RC
B
values. It can be approximately cal-
Slow Decay
t
RCFALL
1 s t
1 s t
t
t
RCRISE
OFF
C
BLANK
DT
D
A
(or RC
ON
B
).