TE –
SOLE
– OB
High Voltage 1 REN Ring Generator
Ordering Information
Package Options
Device
HV421
8-Lead SO
HV421LG
HV421
Features
Processed with HVCMOS
®
technology
4.75V to 9.5V operating supply voltage
DC to AC conversion
1 REN load capacity
Adjustable ring frequency from 15Hz to 60Hz
Adjustable converter frequency
Enable/Disable function
General Description
The Supertex HV421 is a high voltage ring generator designed
to drive 1 North American REN (ringer equivalent number) from
a 5V source. The HV421 has an internal DC-DC converter which
converts the 5V DC supply to a nominal 68V DC connected to the
V
PP
pin. The DC-DC converter frequency of the HV421 is set by
an external resistor connected between R
SW
and V
DD
. The
ringing signal is generated by a high voltage H-bridge which
produces two square waves which are 180 degrees from each
other. The ringing frequency of the H-bridge is set by an external
resistor connected between R
RING
and V
DD
.
11
Absolute Maximum Ratings*
Supply Voltage, V
DD
Output Voltage, V
cs
Operating Temperature Range
Storage Temperature Range
SO-8 Power Dissipation
Note:
*All voltages are referenced to GND.
Pin Configuration
-0.5V to +10V
-0.5V to +120V
0°C to +85°C
-65°C to +150°C
400mW
ςΑ
V
DD
R
SW
V
PP
L
x
1
2
3
4
8
7
6
5
R
ring
Gate
Gate
GND
Top View
SO-8
11-1
HV421
Electrical Characteristics
DC Characteristics
Symbol
R
DS(ON)
I
DDQ
I
DD
I
IN
V
PP
F
RING
D
RING
fsw
Dsw
(V
DD
=5.0V, R
RING
=30MΩ, R
SW
=1.3MΩ, L
X
=330µH, T
A
=25°C)
Parameter
On-resistance of switching transistor
Quiescent V
DD
supply current
Input current going into the V
DD
pin
Input current including inductor current
Output voltage on V
PP
Ring frequency
Ringing frequency duty cycle
Switching transistor frequency
Switching transistor duty cycle
65
20
170
68
25
50
35
88
30
Min
Typ
3.5
Max
5
50
300
220
Units
Ω
nA
µA
mA
V
Hz
%
KHz
%
V
IN
=5.0V. See Figure 1.
I=100mA
R
SW
=Low
V
IN
=5.0V. See Figure 1.
V
IN
=5.0V. See Figure 1.
V
IN
=5.0V. See Figure 1.
V
IN
=5.0V. See Figure 1.
Conditions
Recommended Operating Conditions
Symbol
V
DD
T
A
Supply voltage
Operating temperature
Parameter
Min
4.75
0
Typ
Max
9.5
85
Units
V
°C
Conditions
TE –
SOLE
Enable/Disable Table
– OB
Symbol
EN-L
EN-H
Parameter
Min
0
V
DD
-0.5
Typ
Max
0.5
V
DD
Units
V
V
Logic input low voltage
Logic input high voltage
Conditions
11-2
HV421
Block Diagram
TE –
SOLE
– OB
L
x
V
PP
DC-DC
Converter
Gate
V
DD
R
SW
R
RING
GND
Ring
Frequency
Level
Translator
Gate
Typical Application
ON = 4.75V
OFF = 0V
30M
0.01µF
Q1
D1
11
6.8K
1
330µH
V
DD
R
SW
V
PP
L
x
R
RING
Gate
Gate
GND
HV421LG
8
7
D2
1.3M
2
3
Q2
2.2K
Q3
D3
V
IN
4.75V
160mA
6
1N4148
4
5
2.2K
8.0µF
Load
D4
1.0µF
0.01µF
Q4
Q1, Q3 = Supertex VN2110K1
Q2, Q4 = Supertex VP2110K1
D1–D4 = 5.1V Zener diode
V
OUT
=
±60V
Freq = 25Hz
Figure 1: 1 REN Ring Generator
11-3
HV421
Application Description
The Supertex HV421LG is a high voltage 1 REN ring genera-
tor. A typical application circuit is shown in Figure 1. There are
four basic parts to the circuit; the DC-DC converter, level
translation of the ringing frequency, enable/disable function,
and an external source follower buffer stage.
DC-DC converter
The DC-DC converter consists of a 330µH inductor, 1N4148
diode, 1.0µF capacitor and 1.3MΩ resistor. The 1.3MΩ resistor
sets the DC-DC converter frequency. Energy is stored in the
330µH inductor when the switching transistor is turned on and
is released into the 1.0µF capacitor when the switch is in the
off state. A high voltage DC will develop at V
PP
which is
internally connected to the level translator.
Level translation of the ringing frequency
The ringing frequency is set by a 30MΩ resistor. A low voltage
square wave is generated with a nominal frequency of 25Hz.
Lower ringing frequencies can be obtained by using resistors
greater than 30MΩ. The signal is then level translated to swing
from 0V to the V
PP
voltage. An inverted and a noninverted
output are generated (gate and gate bar).
Enable/Disable function
The HV421 can be enabled by connecting the 1.3MΩ and
30MΩ resistors to the same potential as V
DD
and disabled by
connecting them to ground.
External source follower buffer stage
The gate and gate bar are connected to an external source
follower stage. Supertex transistors VP2110K1 and VN2110K1
are used for the buffering. Zener diodes clamps across the
gates are recommended as a precaution but not required.
The voltage seen by the load is
±60V.
A 6.8KΩ resistor in
series with an 8.0µF capacitor is used to simulate 1 North
American REN (ringer equivalent number). The main specifi-
cations for the Supertex source follower transistors are listed
below.
ETE –
SOL
– OB
Device
VN2110
VP2110
Type
N-Channel
P-Channel
Breakdown
Voltage, BV
DSS
100V
-100V
Gate Threshold
Voltage, V
GS(th)
0.8V to 2.4V
-1.5V to -3.5V
On-Resistance, R
DS(ON)
6.0Ω at V
GS
=5V
11Ω at V
GS
=-5V
Package Options
TO-92, SOT-23
TO-92, SOT-23
11-4
HV430
Advanced Information
High-Voltage Ring Generator
Ordering Information
Operating Voltage
V
PP1
- V
NN1
325V
Package Options
SOW-20
HV430WG
Features
100V
RMS
ring signal
Output over current protection
5.0V CMOS logic control
Logic enable/disable to save power
Fault output for over-current and low voltage lockout
conditions
Adjustable deadband in single-control mode
Power-on reset for hot-swap protection
Low voltage lockout
General Description
The Supertex HV430 is a high voltage PWM ring generator
integrated circuit. The high voltage outputs, Pgate and Ngate,
are used to drive the gates of external high voltage P-channel,
TP2640, and N-channel, TN2640, MOSFETs in a push-pull
configuration. Pulse by pulse over current protection are imple-
mented on both the P-channel and N-channel MOSFETs. The
RESET inputs functions as a power-on reset and as a low
voltage lockout, allowing for hot-swapping capabilities. The
FAULT output indicates over-current and low voltage lockout
conditions. It is active-low and open-drain to allow wire OR’ing of
multiple drivers.
P
GATE
and N
GATE
are controlled independently by logic inputs P
in
and N
in
when the mode pin is at logic high. A logic high on P
in
will
turn on the external P-channel MOSFET. Similarly, a logic high
on N
in
will turn on the external N-channel MOSFET. Lockout
circuitry prevents the N and P switches from turning on simulta-
neously.
For applications where a single control input is desired, the mode
pin should be connected to Gnd. The PWM control signal is then
input to the N
in
pin. A user-adjustable deadband in the control
logic assures break-before-make on the outputs, thus avoiding
cross conduction on the high voltage output during switching. A
logic high on Nin will turn the external P-Channel MOSFET on
and the N-Channel off, and vice versa. The IC can be powered
down by applying a logic low on the Enable pin, placing both
external MOSFETs in the off state.
11
Applications
High voltage ring generator
Set-top/Street box ring generator
Absolute Maximum Ratings
V
PP1
- V
NN1
, power supply voltage
V
PP1
, positive high voltage supply
V
PP2
, positive gate voltage supply
V
NN1
, negative high voltage supply
V
NN2
, negative gate voltage supply
V
DD
, logic supply
Storage temperature
Power dissipation
+340V
+220V
+220V
-220V
-220V
+7.5V
-65°C to +150°C
800mW
11-5
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