el7516 Intersil Corporation, el7516 Datasheet - Page 8

• Manufacturer Part Number: el7516
• Description: 600khz/1.2mhz Pwm Step-up Regulator
• Manufacturer: Intersil Corporation

Typical Performance Curves
Applications Information
The EL7516 is a high frequency, high efficiency boost
regulator operated at constant frequency PWM mode. The
boost converter stores energy from an input voltage source
and delivers it to a higher output voltage. The input voltage
range is 2.5V to 5.5V and the output voltage range is 5V to
18V. The switching frequency is selectable between 600KHz
and 1.2MHz, allowing smaller inductors and faster transient
response. An external compensation pin gives the user
greater flexibility in setting output transient response and
tighter load regulation. The converter soft-start characteristic
can also be controlled by external C
pin allows the user to completely shut-down the device.
Boost Converter Operations
Figure 28 shows a boost converter with all the key
components. In steady state operating and continuous
conduction mode where the inductor current is continuous,
200mV/DIV
FIGURE 27. PACKAGE POWER DISSIPATION vs AMBIENT
FIGURE 25. TRANSIENT RESPONSE - 1.2MHz
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
V
V
I
OUT
TEMPERATURE
870mW
IN
OUT
= 3.3V
= 50mA TO 300mA
= 12V
25
AMBIENT TEMPERATURE (°C)
0.1ms/DIV
50
8
SS
75
capacitor. The SHDN
85
(Continued)
100
125
EL7516
the boost converter operates in two cycles. During the first
cycle, as shown in Figure 29, the internal power FET turns
on and the Schottky diode is reverse biased and cuts off the
current flow to the output. The output current is supplied
from the output capacitor. The voltage across the inductor is
V
is the inductance. The inductance is magnetized and energy
is stored in the inductor. The change in inductor current is:
D
ΔV
ΔI
Δt1
IN
FIGURE 28. PACKAGE POWER DISSIPATION vs AMBIENT
L1
=
O
and the inductor current ramps up in a rate of V
Duty Cycle
=
=
=
FIGURE 26. TYPICAL SHDN INPUT LEVEL vs V
--------- -
f
Δt1
SW
--------------- -
C
D
I
OUT
OUT
0.6
0.5
0.4
0.3
0.2
0.1
5
4
3
2
1
0
0
×
3
0
JEDEC JESD51-3 LOW EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
V
---------
TEMPERATURE
486mW
×
L
IN
Δt
1
3.5
25
AMBIENT TEMPERATURE (°C)
SHDN TURN ON
4
50
V
IN
4.5
(V)
75
SHDN TURN OFF
5
85
100
5.5
October 9, 2007
(EQ. 1)
125
IN
6
IN
FN7333.6
/ L, L