EVAL6730 STMicroelectronics, EVAL6730 Datasheet - Page 29
![EVAL BOARD FOR L6730XX](/photos/9/30/93060/eval6730_sml.jpg)
EVAL6730
Manufacturer Part Number
EVAL6730
Description
EVAL BOARD FOR L6730XX
Manufacturer
STMicroelectronics
Type
Motor / Motion Controllers & Driversr
Datasheets
1.L6730TR.pdf
(52 pages)
2.L6730DTR.pdf
(50 pages)
3.EVAL6730.pdf
(9 pages)
4.EVAL6732.pdf
(43 pages)
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
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
L6730C - L6730D
5.14.2 No-sink at zero current operation
Figure 24. 12V -> 3.3V@0A in no-sink
The L6730C can work in no-sink mode. If output current is zero the converter skip some pulses
and works with a lower switching frequency. Between two pulses can pass a relatively long time
(say 200-300µs) during which there’s no switching activity and the current into the inductor is
zero. In this condition the phase node is at the output voltage and in some cases this is not
enough to keep the bootstrap cap charged. For example, if Vout is 3.3V the voltage across the
bootstrap cap is only 1.7V. The high-side MOSFET cannot be effectively turned-on and the
regulation can be lost. Thanks to the “bootstrap anti-discharging system” the bootstrap cap is
always kept charged. The following picture shows the behaviour of the device in the following
conditions: 12V 3.3V@0A.
It can be observed that between two pulses trains the low-side is turned-on in order to keep the
bootstrap cap charged.
Minimum Bootstrap Voltage
Pulse train
I
L
V
Device description
PHASE
29/50