Datasheet
Single-chip Type with Built-in FET Switching Regulators
Simple Step-down
Switching Regulators
with Built-in Power MOSFET
BD9G101G
●General
Description
The BD9G101G is switching regulator with integrated
internal high-side 42V Power MOSFET.
It provides 0.5A DC output with small SSOP6 package.
Operating frequency is fixed 1.5MHz, allowing the use
of small inductor and ceramic capacitor.
The components of phase compensation is built in.
●Features
■
High and Wide Input Range (VCC=6V~42V)
■
45V/800mΩ Internal Power MOSFET
■
1.5MHz Fixed Operating Frequency
■
Feedback Pin Voltage 0.75V±1.5%
■
Internal compensated
■
Internal Over Current protection, Under
Voltage Locked Out, Thermal shutdown
■
0μA Shutdown Supply Current (Ist=0uA)
■
Small package SSOP6
●Key
Specifications
■
Input Voltage
■
Ref. Precision (Ta=25℃)
(Ta=-25~105℃)
■
Max Output Current
■
Operating Temperature
■
Max Junction Temperature
●Packages
SSOP6
6½42 [V]
±1.5[%]
±2.0[%]
0.5 [A] (Max.)
-40℃~105℃
150℃
2.90
㎜×2.80 ㎜×1.25 ㎜
SSOP6
●Applications
■
Industrial distributed power applications
■
Automotive Applications
■
Battery powered equipment
■
OA instruments
●Typical
Application Circuits
15000pF
L1:6.8uH
BST
LX
D1
GND
VCC
C2:10μF/10V
5V/0.5A
VCC
C1:4.7μF/50V
FB
680Ω
0.1uF
3.9kΩ
EN
ON/OFF control
Figure 1. Typical Application Circuit
○Structure：Silicon
Monolithic Integrated Circuit
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○This
product is not designed for normal operation with in a radioactive.
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BD9G101G
●Pin
Configuration
BST
GND
1
2
3
6
5
4
LX
VCC
FB
EN
Figure 2. Pin Configuration (TOP VIEW)
●Pin
Description
Pin No.
1
2
3
4
5
6
Pin Name
BST
GND
FB
EN
VCC
LX
Description
The pin is power supply for floating Power NMOS driver. Connected a
bypass capacitor between the pin and Lx pin for bootstrap operation.
Ground. It should be connected as possible to the output capacitor ground
avoiding the high current switch paths.
Voltage feedback pin. This pin is error-amp input, the DCDC is set 0.75V at
this pin with feed-back operation.
Enable input pin. The DCDC is start-up to apply over 2.0V.
This pin is pull-down about 550kΩ, the DCDC is shutdown to open or apply
under 0.8V.
Input supply. It should be connected as near as possible to the bypass
capacitor.
Power FET switch output. It should be connected as near as possible to the
schottky barrier diode, and inductor.
●Block
Diagram
ON/OFF
EN
VCC
TSD
UVLO
Reference
VREF
REG
Current Sense
AMP
OCP
shutdown
FB
0.75V
-
+
+
Error
AMP
Σ
Current
Comparator
-
R Q
+
S
BST
800mΩ
Soft
Start
Oscillator
1.5MHz
LX
VOUT
GND
Figure 3. Block Diagram
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BD9G101G
●Description
of Blocks
1.
Reference
This block generates reference voltage and current. It start operation by applying EN more than 2.0V.
It provides reference voltage and current to error-amp , oscillator ,and etc.
2.
REG
This is a gate drive voltage generator and 4.2V regulator for internal circuit power supply.
3.
OSC
This is a precise wave oscillation circuit with operation frequency fixed to 1.5MHz fixed.
To protect from output shorted to GND, Frequency fold-back function is built in.
Soft Start
This block does Soft Start to the output voltage of DC/DC comparator, and prevents in-rush current during Start-up.
Soft Start Time depend on application and start-condition because Frequency fold-back function is built in.
4.
5.
ERROR AMP
This is an error amplifier what detects output signal, and outputs PWM control signal.
Internal reference voltage is set to 0.75V. Also, the BD9G101G has internal phase compensated element between
input and output.
6.
Current Comparator
This is a comparator that outputs PWM signal from current feed-back signal and error-amp output for current-mode.
7.
Nch FET SW
This is an 45V/800mΩ Power Nch MOSFET SW that converts inductor current of DC/DC converter.
8.
UVLO
This is a low voltage error prevention circuit.
This prevents internal circuit error during increase of power supply voltage and during decline of power supply voltage.
It monitors VCC pin voltage, And when VCC voltage becomes 5.4V and below, it turns OFF all output FET and turns
OFF DC/DC comparator output, and Soft Start circuit resets.
Now this Threshold has hysteresis of 200mV.
EN
When a Voltage of 2.0V or more is applied, it turns ON, at Open or 0V application, it turns OFF.
About 550kΩ Pull-down Resistance is contained within the Pin.
9.
10. OCP
The current of power MOSFET is limited by this function.
The power MOSFET current is sensed by current sense FET. If the current of power MOSFET is over 1.2A(typ), this
function reduce duty by pulse –by- pulse and restrict the and restraint on over current.
11.TSD
Circuit for preventing malfunction at high Temperature .
When it detects an abnormal temperature exceeding Tj=175℃, it turns OFF DC/DC Comparator Output. The threshold
of TSD has Hysteresis(25℃). If Temperature falls 150℃,the IC automatically returns.
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BD9G101G
●Absolute
Maximum Ratings
Item
VCC
Maximum input current
BST to GND
BST to LX
EN
Lx
FB
Power Dissipation
Operating Temperature
Storage Temperature
Junction Temperature
Symbol
VCC
Imax
VBST
⊿VBST
VEN
VLx
VFB
Pd
Topr
Tstg
Tjmax
Ratings
45
1.0
50
7
45
45
7
0.675
(*1)
Unit
V
A
V
V
V
V
V
W
℃
℃
℃
-40½+105
-55½+150
150
(*2)
(*1)During mounting of 70×70×1.6t mm 1layer board.Reduce by 5.4mW for every 1℃ increase. (Above 25℃)
(*2)Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator
will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage.
thermal shutdown engages at Tj=175℃(typ) and disengages at Tj=150℃ (typ)
●Electrical
Characteristics (Unless
otherwise specified Ta=25℃, VCC=24V, Vo=5V,EN=3V
)
Limit
Min
－
－
5.1
－
1.3
85
0.739
0.735
-100
1.2
-
－
－
0.85
2.0
-0.3
2.7
Typ
0
0.7
5.4
200
1.5
-
0.750
0.750
0
4.0
3
800
100
1.2
－
－
5.5
Max
5
1.2
5.7
300
1.7
-
0.761
0.765
100
-
-
－
－
－
VCC
0.8
11
Parameter
【Circuit
Current】
Stand-by Current
Operating Current
【Under
Voltage Lock Out (UVLO)】
Threshold Voltage
Hysteresis width
【Oscillator】
Switching Frequency
Max Duty Cycle
【Error
AMP】
FB Pin Reference Voltage
FB Pin Bias Current
Soft-Start Time
【Current
Comparator】
Trans-conductance
【Output】
Nch MOSFET ON Resistance
Min ON Time
Switch Current Limit
【CTL】
EN Thresohold Voltage
EN Input Bias Current
◎
Not designed to withstand radiation.
Symbol
Unit
Condition
Ist
Icc
Vuv
Vuvhy
fosc
Dmax
VFBN
VFBA
IFB
Tsoft
G
CS
RonH
Tmin
Iocp
ON
VENON
µA
mA
V
mV
MHz
%
V
V
nA
ms
A/V
mΩ
nsec
A
V
V
µA
VEN=0V
FB=1.2V
Ta=25℃
Ta=-25~105℃
VFB=2.0V
OFF VENOFF
REN
VEN=3V
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BD9G101G
●Operating
Ratings
Ratings
Min
6
1.0
(*3)
Item
Input Voltage
Output Voltage
Symbol
VCC
VOUT
Typ
-
-
-
Max
42
VCC×0.7
500
(*4)
Unit
V
V
mA
Output Current
IOUT
-
(*3)Restricted by minimum on pulse typ. 100nsec
(*4)Restricted by maxduty ,Ron and BST-UVLO.
●input
and output voltage restriction
The input voltage range of BD9G101G is limited by Ron, Maxduty(min85%) and preventing malfunction at low voltage
between BST and LX(BST-UVLO).
①
BST-UVLO
BSTUVLO is the function that prevent the IC from abnormal operation that is caused by shortage of charge of High-SideFET
driving. If the voltage between BST and LX is lower than 1.5V, High-Side FET is turned off and there are new pass to charge
voltage VCC to BST. BST voltage is charged by Vcc and goes over BST-UVLO threshold. As a result , BST-UVLO is turned
off.
The condition that BST-UVLO is working property is
VCC>>(BST-UVLO threshold + Vf )+ Vout.
Therefore maximum output voltage is lower than Vin -3V.
4.2V
BST charging current (normal mode)
BST
BSTUVLO
BST charging current
(BST-UVLO mode)
VCC
NchFET OFF
(BST-UVLO mode)
LX
Figure 4. BST-UVLO image
※When
operation can be considered by Vin-Vout<3V, output voltage leaps up to near input voltage by BSTUVLO operation at
the time of a light load.
The waveform of operation and a mechanism are shown.
①BSTUVLO
detection
→Nch
MOS FET is turned OFF
↓
②Vout、Lx
are discharged
⇒ErrorAMP
output is raised
↓
Vout
1v/div
③
The voltage between BST-Lx is secured enough
→BSTUVLO
release
↓
④
In order to carry out a start of operation with Max Duty
cycle, an output leaps up.
↓
Figure 5. BSTUVLO operation waveform
Vout=5V Vin=7V Iout=0mA
⑤
The voltage between BST-Lx is insufficient.
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