40–100 V MOSFETs
Low voltage DC motor control
>100 V MOSFETs
Active clamp in AC/DC conversion
>100 V MOSFETs
UHP lamp driver
Triacs and SCRs
Triac commutation monitoring
without sensing resistor
Description
In controlling the speed and direction of low voltage brushed
and brushless DC motors, power MOSFETs provide robust
and easy-to-use solutions and have largely replaced their
bipolar counterparts.This is because they offer several
features which make them uniquely suitable for operation in
DC motor control circuits.
MOSFETs are extremely easy to turn on or off, simply
requiring that the gate capacitance is charged to the
necessary voltage level. Once turned on or off, the MOSFET
gate draws no further current from the drive circuit. Modern
MOSFET technology enables devices with R
DS(on)
figures of
less than 10 mΩ, ensuring that even at high current levels,
on-state losses are extremely low. In bridge configurations,
the MOSFETs built-in body diode may be used to conduct
freewheeling currents, eliminating the need for external
parallel diodes.
Benefits
• Very low R
DS(on)
ensures low on-state loss
• Fast switching
• Low loss operation reduces heatsinking and increases
battery life
• Robust, handles large current spikes without damage
Suitable Products
• PHP222NQ04LT
• PHB222NQ04LT
• PHP193NQ06T
• PHB193NQ06T
• PHP73N06T
• PHB73N06T
• PHP110NQ08T
• PHB110NQ08T
Description
The active clamp topology allows for a more efficient
method of transformer core reset in isolated flyback and
forward converters. For example in a forward converter,
core reset is traditionally achieved by the use of an ‘RCD’
clamp, resulting in a loss of core magnetising energy as it
dissipates in the resistive part of the clamp. An active
clamp circuit allows the core magnetising energy to be
recovered and returned to the supply, improving overall
converter efficiency.This is achieved by the circuit
comprised of the transformer, CCLAMP and MOSFET Q1
– a lower current N-channel MOSFET with a voltage
rating of 150V or 200 V. A second benefit offered by the
active clamp topology is that the voltage appearing across
the primary side switch MOSFET (Q2) is reduced,
compared to other core reset methods.This also has less
variation with the input voltage allowing a lower voltage
rated device to be used in the Q2 position.
Suitable Products for Q1 and Q2
• PML260SN (200V, 294 mΩ)
• PSMN063-150D (150V, 63 mΩ, DPAK)
• PHK5NQ15T (150V, 75 mΩ, SO8)
• PHD22NQ20T (200V, 120 mΩ, DPAK)
• PHK4NQ20T (200V, 130 mΩ, SO8)
• PHD14NQ20T (200V, 230 mΩ, DPAK)
Description
Ultra high pressure (UHP) lamps in projectors are often
driven by a full bridge resonant inverter, with N-channel
MOSFETs as power switches involved in converting the
DC input voltage to an AC voltage.
In the circuit below, a full bridge converts the DC rail to
a low frequency square AC voltage that supplies the lamp.
The DC voltage is typically regulated by a step-down
converter, which is normally connected to an AC mains
PFC pre-conditioner with nearly constant voltage (e.g. 380 V)
and provides a voltage within the 50 V to 175 V range.
The MOSFETs drain-source voltage must be selected to
withstand the maximum voltage that can occur on the
DC supply.The products listed below are ideal for lamp
powers ranging from 40 W to about 200 W.
A driver IC, such as the Philips UBA2033, provides the
drive for all the N-channel MOSFETs in the full bridge
configuration.
Benefits
• Low on-state losses increase inverter efficiency
• Easy gate driving due to low input capacitance
• Flexible choice of packages,V
DS
and R
DS(on)
Suitable Products
Power MOSFETs
• PHP33NQ20T
• PHB33NQ20T
• PHD22NQ20T
• PHP45NQ15T
• PHB45NQ15T
Driver IC
• UBA2033
Description
Intelligent, microcontroller-based triac management allows
continuous conduction or phase control of any
unspecified load without the need for a current sense
resistor.The closed-loop system adjusts automatically to
apply sufficient current to guarantee triggering, while
minimizing current drawn from the driver supply.
Combining Philips’ Hi-Com triacs and low-cost LPC (Low
Pin Count) microcontrollers, together with the necessary
software code, can achieve any triac control function
simply, cheaply and reliably. Once the system has been
designed, its closed-loop functionality ensures success for
any load in a wide range of applications including solid-
state relays, domestic appliances and personal care
products, as well as leisure and industrial equipment.
Benefits
• Predicts imminent triac commutation
• No current sense resistor required
• Microcontroller applies gate current only when needed
• Self adjusts for any load
• Enables simple, reliable, one-for-all design-and-forget
triac control systems
Suitable Products
Triac
• BTA2xx
Microcontroller
• 87LPC764
Circuit Diagram
Circuit Diagram
+V
IN
Circuit Diagram
Circuit Diagram
dc voltage rail
HR
HL
R
>
100
Ω
Q1
M
D1
Q1
Q3
(active clamp)
CCLAMP
transformer
primary
low voltage
M
Q2
C
i
EXTERNAL
OSCILLATOR
CONTROL
CIRCUIT
Q1
Q2
Q4
(primaire
side switch)
0V
bra533
bra515
C3
GND
R
>
100
Ω
−LVS
GHR
1
28
EXTOR
FSR
2
27
+LVS
SHR C1
3
26
4
25
R
>
100
Ω
5
24
HV
GLR
6
23
PGND
7
22
8
UBA2033TS
21
V
DD
GLL
9
20
SU
19
10
DO
18
11
SHL
BD
17
12
RC
FSL
16
13
SGND
GHL C2
15
14
+5V
Trigger current
>50mA
56R
22k
Gate
voltage
monitor
IGNITOR
LR
LL
R
>
100
Ω
87LPC764
microcontroller
BTA2**
Hi-Com
triac
L
BZX79C5V6
1000uF
16V
+
+
-
bra517
Mains
supply
N
2k2
100k
Comparators
+
120 V
Q1
Q3
Q5
VIN = 75 V
1N4148
R-C
mains
dropper
0V
-
48 V
AC
RECTIFIER
PFC
22k
100k
Any load
M
Q1 VDS
(20 V/div)
STEP-DOWN
CONVERTER
FULL
BRIDGE
IGNITION
UHP
LAMP
35 V
Q2
Q4
Q6
Low current
logic supply
Window
comparator
0V
bra516
LAMP DRIVER CONTROL CIRCUITRY
MSE150
bra518
52
53