SI9130DB Vishay, SI9130DB Datasheet - Page 10

• Manufacturer Part Number: SI9130DB
• Description: Pulse Width Modulation (PWM) Controller IC
• Manufacturer: Vishay

Specifications of SI9130DB

• Silicon Manufacturer: Vishay
• Application Sub Type: Pin-programmable Controller
• Kit Application Type: Power Management
• Silicon Core Number: SI9130
• Kit Contents: Board
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Si9130
Vishay Siliconix
3.3-V and 5-V Switching Controllers
Each PWM controller on the Si9130 is identical with the exception
of the preset output voltages. The controllers only share three
functional blocks (see Figure 3): the oscillator, the voltage
reference (REF) and the 5-V logic supply (V
controllers are independently enabled with pins ON
respectively. The PWMs are a direct-summing type, without the
typical integrating error amplifier along with the phase shift which
is a side effect of this type of topology. Feedback compensation
is not needed, as long as the output capacitance and its ESR
requirements are met, according to the Design Considerations
section of this data sheet.
www.vishay.com
10
5-V Reference)
(or Internal
ON_
SS_
3.3 V
REF,
25 mV
4 mA
Minimum Current
(Pulse-Skipping Mode)
Slope
Comp
FIGURE 3. Si9130 Controller Block Diagram
3.3 V
60 kHz
L
LPF
). The 3.3-V and 5-V
Synchronous
Rectifier Control
Summing
Comparator
30R
1R
V
3
R
S
L
and ON
Q
0 mV to
100 mV
5
1X
,
Current
Limit
The main PWM comparator is an open loop device which is
comprised of three comparators summing four signals: the
feedback voltage error signal, current sense signal,
slope-compensation ramp and voltage reference as shown in
Figure 3. This method of control comes closer to the ideal of
maintaining the output voltage on a cycle-by-cycle basis.
When the load demands high current levels, the controller is in
full PWM mode. Every cycle from the oscillator asserts the
output latch and drives the gate of the high-side MOSFET for
a period determined by the duty cycle (approximately
V
OU
T/V
IN
R
S
Q
OSC
100%) and the frequency.
Through
Control
Shoot-
Level
Level
Shift
Shift
CS_
FB_
BST_
DH_
LX_
V
DL_
PGND
L
S-40805—Rev. F, 26-Apr-04
Document Number: 70190