ICL7667CPAZ Intersil, ICL7667CPAZ Datasheet - Page 6

• Manufacturer Part Number: ICL7667CPAZ
• Description: IC MOSFET DRIVER DUAL HS 8DIP
• Manufacturer: Intersil

Specifications of ICL7667CPAZ

• Configuration: Low-Side
• Input Type: Inverting
• Delay Time: 20ns
• Current - Peak: 1A
• Number Of Configurations: 2
• Number Of Outputs: 2
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• High Side Voltage - Max (bootstrap): -
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

Direct Drive of MOSFETs
Figure 11 shows interfaces between the ICL7667 and typical
switching regulator ICs. Note that unlike the DS0026, the
ICL7667 does not need a dropping resistor and speedup
capacitor between it and the regulator IC. The ICL7667, with
its high slew rate and high voltage drive can directly drive the
gate of the MOSFET. The SG1527 IC is the same as the
SG1525 IC, except that the outputs are inverted. This
inversion is needed since ICL7667 is an inverting buffer.
FIGURE 9. MOSFET GATE DYNAMIC CHARACTERISTICS
18
16
14
12
10
-2
8
6
4
2
0
0
2
I
212pF
D
= 1A
4
GATE CHARGE - Q
6
680pF
TL494
GND
V
15V
+V
DD
8
C
= 50V
10
C1
C2
E1
E2
6
G
12
(NANO-COULOMBS)
+15V
630pF
14
V
SG1527
DD
GND
15V
+V
FIGURE 10. DIRECT DRIVE OF MOSFET GATES
1K
1K
= 200V
C
16
V
DD
A
B
= 375V
18
ICL7667
+V
-V
20
FIGURE 10A.
FIGURE 10B.
ICL7667
ICL7667
+V
-V
IRF730
Transformer Coupled Drive of MOSFETs
Transformers are often used for isolation between the logic
and control section and the power section of a switching
regulator. The high output drive capability of the ICL7667
enables it to directly drive such transformers. Figure 11
shows a typical transformer coupled drive circuit. PWM ICs
with either active high or active low output can be used in
this circuit, since any inversion required can be obtained by
reversing the windings on the secondaries.
Buffered Drivers for Multiple MOSFETs
In very high power applications which use a group of
MOSFETs in parallel, the input capacitance may be very large
and it can be difficult to charge and discharge quickly. Figure
13 shows a circuit which works very well with very large
capacitance loads. When the input of the driver is zero, Q
held in conduction by the lower half of the ICL7667 and Q
clamped off by Q
off and a current pulse is applied to the gate of Q
upper half of the ICL7667 through the transformer, T
about 20ns, T
and the bootstrap circuit of C
circuit may not be needed at frequencies greater than 10kHz
since the input capacitance of Q
+165V
IRF730
IRF730
DC
1
saturates and Q
+165V
1
IRF730
. When the input goes positive, Q
DC
1
, D
2
2
1
is held on by its own C
discharges slowly.
and R
1
V
. This bootstrap
OUT
2
by the
1
1
is turned
April 4, 2006
. After
FN2853.5
GS
1
2
is
is