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參數(shù)資料
| 型號： | HV9123 |
| 廠商： | ELAN Microelctronics Corp . |
| 英文描述： | High-Voltage Current-Mode PWM Controller(輸入范圍10V-450V，高壓電流型脈寬調(diào)制控制器) |
| 中文描述： | 高電壓電流模式PWM控制器（10V的輸入范圍- 450V，高壓電流型脈寬調(diào)制控制器） |
| 文件頁數(shù)： | 6/7頁 |
| 文件大?。?/td> | 49K |
| 代理商： | HV9123 |
14-36
HV9120/HV9123
Test Circuits
Detailed Description
Preregulator
The preregulator/startup circuit for the HV912x consists of a high-
voltage n-channel depletion-mode DMOS transistor driven by an
error amplifier to form a variable current path between the V
IN
terminal and the V
DD
terminal. Maximum current (about 20 mA)
occurs when V
DD
= 0, with current reducing as V
DD
rises. This path
shuts off altogether when V
DD
rises to somewhere between 7.8
and 9.4V, so that if V
DD
is held at 10 or 12V by an external source
(generally the supply the chip is controlling) no current other than
leakage is drawn through the high voltage transistor. This mini-
mizes dissipation.
An external capacitor between V
DD
and V
SS
is generally required
to store energy used by the chip in the time between shutoff of the
high voltage path and the V
DD
supply’s output rising enough to
take over powering the chip. This capacitor should have a value
of 100X or more the effective gate capacitance of the MOSFET
being driven, i.e.,
C
storage
≥
100 x (gate charge of FET at 10V
÷
10V)
as well as very good high frequency characteristics. Stacked
polyester or ceramic caps work well. Electrolytic capacitors are
generally not suitable.
A common resistor divider string is used to monitor V
DD
for both
the undervoltage lockout circuit and the shutoff circuit of the high
voltage FET. Setting the undervoltage sense point about 0.6V
lower on the string than the FET shutoff point guarantees that the
undervoltage lockout always releases before the FET shuts off.
Bias Circuit
An external bias resistor, connected between the bias pin and V
SS
is required by the HV912x to set currents in a series of current
mirrors used by the analog sections of the chip. Nominal external
bias current requirement is 15 to 20
μ
A, which can be set by a
390K
to 510K
resistor if a 10V V
DD
is used, or a 510k
to
680K
resistor if V
DD
will be 12V. A precision resistor is not
required;
±
5% is fine.
Clock Oscillator
The clock oscillator of the HV912x consists of a ring of CMOS
inverters, timing capacitors, a capacitor discharge FET, and, in
the 50% maximum duty cycle versions, a frequency dividing flip-
flop. A single external resistor between the OSC In and OSC Out
pins is required to set oscillator frequency (see graph). For the
50% maximum duty cycle versions the Discharge pin is internally
connected to V
SS
(ground). For the 99% duty cycle version,
Discharge can either be connected to V
SS
directly or connected to
V
SS
through a resistor used to set a deadtime.
One difference exists between the Supertex HV912x and competi-
tive 912x’s: The oscillator is shut off when a shutoff command is
received. This saves about 150
μ
A of quiescent current, which
aids in the construction of power supplies to meet CCITT speci-
fication I-430, and in other situations where an absolute minimum
of quiescent power dissipation is required.
Reference
The Reference of the HV912x consists of a stable bandgap
reference followed by a buffer amplifier which scales the voltage
up to approximately 4.0V. The scaling resistors of the reference
buffer amplifier are trimmed during manufacture so that the output
of the error amplifier when connected in a gain of –1 configuration
is as close to 4.000V as possible. This nulls out any input offset
of the error amplifier. As a consequence, even though the ob-
served reference voltage of a specific part may not be exactly
4.0V, the feedback voltage required for proper regulation will be.
A
≈
50K
resistor is placed internally between the output of the
reference buffer amplifier and the circuitry it feeds (reference
output pin and non-inverting input to the error amplifier). This
allows overriding the internal reference with a low-impedance
voltage source
≤
6.0V. Using an external reference reinstates the
input offset voltage of the error amplifier, and its effect of the exact
value of feedback voltage required. In general, because the
reference voltage of the Supertex HV912x is not noisy, as some
previous examples have been, overriding the reference should
seldom be necessary.
Because the reference of the 912x is a high impedance node, and
usually there will be significant electrical noise near it, a bypass
capacitor between the reference pin and V
SS
is strongly recom-
mended. The reference buffer amplifier is intentionally compen-
sated to be stable with a capacitive load of 0.01 to 0.1
μ
F.
+
–
Reference
V
1
V
2
60.4K
40.2K
1.0V swept 100Hz – 2.2MHz
Tektronix
P6021
(1 turn
secondary)
0.1
μ
F
+10V
(V
DD
)
GND
(–V
IN
)
(FB)
NOTE: Set Feedback Voltage so that
V
COMP
= V
DIVIDE
±
1mV before connecting transformer
Error Amp Z
OUT
+
–
Reference
V
1
V
2
0.1V swept 10Hz – 1MHz
0.1
μ
F
10.0V
4.00V
100K1%
100K1%
PSRR
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| HV9123PJ | High-Voltage Current-Mode PWM Controller |
| HV9120 | High-Voltage Current-Mode PWM Controller |
| HV9120NG | High-Voltage Current-Mode PWM Controller |
| HV9120P | High-Voltage Current-Mode PWM Controller |
| HV9120PJ | High-Voltage Current-Mode PWM Controller |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| HV9123C | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Current-Mode SMPS Controller |
| HV9123NG | 功能描述:電流型 PWM 控制器 HVCMOS 450V 2% Ref RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| HV9123NG-G | 功能描述:電流型 PWM 控制器 HVCMOS 450V 2% Ref RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| HV9123NG-G M901 | 制造商:Supertex Inc 功能描述:Switchmode PWM Controller |
| HV9123NG-G M934 | 制造商:Supertex Inc 功能描述:Switchmode PWM Controller |
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