MIC5011_05 Datasheet, PDF (6/12 Pages) Micrel Semiconductor – Minimum Parts High- or Low-Side MOSFET Driver

MIC5011
Charge Pump
Output Current
250
VGATE =V+
200
150
VGATE =V++5V
100
50
0
0
VS=V ^+–5V
5 10 15 20 25 30
SUPPLY VOLTAGE (V)
Micrel, Inc.
Charge Pump
Output Current
1.0
0.8
VGATE =V+
0.6
0.4
VGATE =V ^++5V
0.2
0
0
C2=1 nF
VS=V ^+–5V
5 10 15 20 25 30
SUPPLY VOLTAGE (V)
Block Diagram
Ground V+ _{C1 Com C2}
4
1 876
MIC5011
Input ²
CHARGE
PUMP
500Ω
LOGIC
5 Gate
12.5V
3 Source
Applications Information
Functional Description (Refer to Block Diagram)
The MIC5011 functions are controlled via a logic block
connected to the input pin 2. When the input is low, all
functions are turned off for low standby current and the
gate of the power MOSFET is also held low through 500Ω
to an N-channel switch. When the input is taken above the
turn-on threshold (3.5V typical), the N-channel switch turns
off and the charge pump is turned on to charge the gate
of the power FET.
The charge pump incorporates a 100kHz oscillator and on-
chip pump capacitors capable of charging 1nF to 5V above
supply in 60µs typical. With the addition of 1nF capacitors
at C1 and C2, the turn-on time is reduced to 25µs typical
(see Figure 3). The charge pump is capable of pumping the
gate up to over twice the supply voltage. For this reason, a
zener clamp (12.5V typical) is provided between the gate
pin 5 and source pin 3 to prevent exceeding the V_GS rating
of the MOSFET at high supplies.
MIC5011
6
July 2005