Vol. 31, No. 4 Journal of SemiconductorsApril 2010
A novel charge pump drive circuit for power MOSFETs?
Wang Songlin(王松林)1;?, Zhou Bo(周波)1;?, Ye Qiang(叶强)2, Wang Hui(王辉)1,
and Guo Wangrui(郭王瑞)1
(1 School of Mechano-Electronic Engineering, Xidian University, Xi’an 710071, China)
(2 Institute of Electronic CAD, Xidian University, Xi’an 710071, China)
Abstract: Novelimprovedpowermetal oxidesemiconductorfieldeffecttransistor(MOSFET)drivecircuitsareintro-
duced. An anti-deadlock block is used in the P-channel power MOSFET drive circuit to avoid deadlocks and improve
the transient response. An additional charging path is added to the N-channel power MOSFET drive circuit to enhance
its drive capability and improve the transient response. The entire circuit is designed in a 0.6 ?m BCD process and
simulated with Cadence Spectre. Compared with traditional power MOSFET drive circuits, the simulation results show
that improved P-channel power MOSFET drive circuit makes the rise time reduced from 60 to 14 ns, the fall time
reduced from 240 to 30 ns, and its power dissipation reduced from 2 to 1 mW, while the improved N-channel power
MOSFET drive circuit makes the rise time reduced from 360 to 27 ns and its power dissipation reduced from 1.1 to
Key words: charge pump; drive circuit; power MOSFET; transient response
DOI: 10.1088/1674-4926/31/4/045009EEACC: 1205; 1210
For low cost, simple topology and no electromagnetic in-
terference, charge pumpsŒ1?4?can be found in wide applica-
tions of digital products. The design of the drive circuit has a
significant influence on the performance of the charge pump.
The transient response and drive capability are two important
factors for power MOSFET drive circuits.
To meet the stringent transient response requirement, the
switching frequency of the power converter should increase.
At high-frequency applications, the effect of the gate drive cir-
cuit of the MOSFET on the overall performance of the con-
verter becomes quite significant. As the switching frequency
increases, the gate drive loss of the power MOSFET, which is
proportional to the switching frequency, increases as well. So
good transient response speed and drive capability are required
for power MOSFET drive circuits. To this aim, much work has
been done in the pastŒ5;6?. Resonant gate drive circuitsthat fea-
ture efficient energy recovery at both charging and discharg-
ing transitions are presented. Several driving circuits allowing
the optimal feeding of the base of a cascade device are dis-
cussed. Some gate drive circuitsŒ7?11?are proposed which not
only save the gate drive loss but also reduce the switching loss.
However, these circuits are complicated or have intrinsic
drawbacks. In this paper, novel power MOSFET drive circuits
with simple structure are proposed and the operation principle
is illustrated in detail. The new drive circuit can greatly im-
prove the transient response and enhance the drive capability.
2. Principle of drive circuit
Figure 1 shows the charge pump topology. The DT block
generates dead time, EA is the error amplifier, the V–I block
converts the voltage signal into a current signal, and P DRIVE
and N DRIVE are the P-channel power MOSFET drive cir-
cuit and N-channel power MOSFET drive circuit respectively.
M1 is the P-channel power MOSFET, and M2 is the N-channel
power MOSFET. For weak drive capabilities, the output signal
of the EA cannot be used directly to drive a power MOSFET,
and the signal needs to be modified first. The V–I block con-
verts the output voltage of the EA into a current signal, then
the current signal is turned into a voltage signal by P DRIVE
or N DRIVE to drive the power MOSFET. The function of the
drive circuit is to transfer signal and enhance drive capability.
3. Drive circuits of the charge pump
3.1. Traditional and improved drive circuits for a P-
channel power MOSFET
Figure 2 shows a traditional P-channel power MOSFET
Fig. 1. Charge pump topology.
* Project supported by the National Natural Science Foundation of China (No. 60876023).
? Corresponding author. Email: firstname.lastname@example.org; Slwang@mail.xidian.edu.cn
Received 28 July 2009, revised manuscript received 23 November 2009
c ? 2010 Chinese Institute of Electronics