LM2595ADPBCKGEVB ON Semiconductor, LM2595ADPBCKGEVB Datasheet - Page 20

• Manufacturer Part Number: LM2595ADPBCKGEVB
• Description: EVAL BOARD FOR LM2595ADPBCKG
• Manufacturer: ON Semiconductor

Specifications of LM2595ADPBCKGEVB

• Design Resources: LM2595ADPBCKGEVB BOM LM2595ADPBCKGEVB Gerber Files LM2595ADPBCKGEVB Schematic
• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 5V
• Current - Output: 1A
• Voltage - Input: 4.5 ~ 40 V
• Regulator Topology: Buck
• Frequency - Switching: 150kHz
• Board Type: Fully Populated
• Utilized Ic / Part: LM2595
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: LM2595ADPBCKG
• Other names: LM2595ADPBCKGEVBOS

Delayed Startup
already mentioned above, which require a higher amount of
startup current. In such cases, if the input power source is
limited, this delayed startup feature becomes very useful.
voltage is applied and the time when the output voltage
comes up, the circuit in Figure 28 can be used. As the input
voltage is applied, the capacitor C1 charges up, and the
voltage across the resistor R2 falls down. When the voltage
on the ON/OFF pin falls below the threshold value 1.3 V, the
regulator starts up. Resistor R1 is included to limit the
maximum voltage applied to the ON/OFF pin. It reduces the
power supply noise sensitivity, and also limits the capacitor
C1 discharge current, but its use is not mandatory.
respectively) ripple voltage exists, a long delay time can
cause some problems by coupling the ripple into the
ON/OFF pin, the regulator could be switched periodically
on and off with the line (or double) frequency.
Undervoltage Lockout
the input voltage reaches a certain threshold level. Figure 29
shows an undervoltage lockout circuit applied to a buck
regulator. A version of this circuit for buck−boost converter
is shown in Figure 30. Resistor R3 pulls the ON/OFF pin
high and keeps the regulator off until the input voltage
reaches a predetermined threshold level with respect to the
ground Pin 3, which is determined by the following
expression:
There are some applications, like the inverting regulator
To provide a time delay between the time when the input
When a high 50 Hz or 60 Hz (100 Hz or 120 Hz
Some applications require the regulator to remain off until
NOTE: This picture does not show the complete circuit.
100 mF
+V
Figure 28. Delayed Startup Circuitry
in
V
C
in
th
[ V
Z1
) 1.0 ) R2
C1
0.1 mF
47 k
R1
+V
in
7
R1
5
ON/OFF
R2
47 k
LM2595
V
BE
( Q1 )
6
GN
D
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20
Adjustable Output, Low−Ripple Power Supply
features an adjustable output voltage is shown in Figure 31.
The input voltage ranges from roughly 3.0 V to 40 V. In order
to achieve a 10 or more times reduction of output ripple, an
additional L−C filter is included in this circuit.
A 1.0 A output current capability power supply that
This regulator delivers 1.0 A into 1.2 V to 35 V output.
1N5242B
1N5242B
NOTE: This picture does not show the complete circuit.
NOTE: This picture does not show the complete circuit.
Figure 29. Undervoltage Lockout Circuit for
+V
Figure 30. Undervoltage Lockout Circuit for
15 k
15 k
R2
Z1
R1
+V
in
10 k
10 k
R2
Z1
R1
in
47 k
R3
47 k
R3
Buck−Boost Converter
Q1
2N3904
Buck Converter
Q1
2N3904
C
100 mF
+V
in
C
100 mF
+V
in
in
2
in
2
5
5
ON/OFF
LM2595
V
ON/OFF
th
LM2595
≈ 13 V
3
3
GND
V
GND
th
≈ 13 V
V
out