CX8808 (1A) 升压芯片

6
2
4
MARK VIEW
Name No. FB 1
PIN DESCRIPTION
I/O Description I Error amplifier inverting input pin Connected a capacitor I Soft start and SCP function pin P IC power supply I Output current setting and control pin O Totem-pole output P IC ground Capacitor and resistor connected for I the frequency of oscillation O Error amplifier compensation output
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BOOST CONVERT CONTROL IC
GENERAL DESCRIPTION
The CX8808 is a boost topology switching regulator control IC for battery-used applications field. The CX8808 includes a totem-pole single output stage for driving NPN transistor or N-MOS, high precision reference (0.5V) for comparing output voltage with feedback amplifier, an internal dead-time control for controlling the minimum duty cycle, programmable soft start with short circuit protection function and logic level control for operating mode or standby mode.
VCC=2V Vout=0.9V Ta=25 ℃
Low Level Output Voltage Vout (V)
Output Source Current Iout (mA)
500 400 300 200 100 0
VCC=2V RB=390Ω Ta=25℃
Δf / ΔT
-
5
-
%
Idle Period Adjustment section PARAMETER Maximum duty cycle SYMBOL TDUTY TEST CONDITIONS RT=3.0kΩ, CT=270pF, VFB=0.8V MIN. 75 TYP. MAX. 85 UNIT %
0.8V 0.1V
Sawtooth wave oscillator
1.25V 1 + 0.5V 8 36 36kΩ
Error Amp. 500KΩ
0.1V PWM Comp. + + + DTC 0.6V
Output drive control circuit 0.22V
5 30 Ω 30k
Soft start & SCP circuit
5 0 -5 -10 -15 -25
0
25
50
75
100
0
-10
-20
-30
-40
-50
Ambient Temperature Ta ( ℃)
High Level Output Current Iout (mA) Figure 4
Figure 3
Low Level Output
600 -60
BR/CTL Pin Current VS Output Source Current
TS S O P 8
TYPICAL APPLICATION
˙Digital Camera ˙PDA ˙Portable Equipment
深圳尚亿微电子有限公司
１３５／０９６８／５２８６ Ｑ：１８３／９８４５／８９８
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FUNCTIONAL BLOCK DIAGRAM
3 7
Reference voltage supply
Soft Start section (S.S.) PARAMETER Input source current Soft start threshold voltage SYMBOL ISS VSST TEST CONDITIONS VSCP= 0V -MIN. -1.5 0.8 TYP. -1.0 0.9 MAX. -0.7 1.0 UNIT μA V
Output source current Output sink current
Output section PARAMETER Output high voltage Output high voltage Output saturation voltage Output saturation voltage Output source current Output sink current Internal pull-down resistor SYMBOL VOH1 VOH2 VOL1 VOL2 IOSOURCE IOSINK RO TEST CONDITIONS RB=390Ω, IO=-15mA RB=750Ω, IO=-10mA, VCC= 1.8V RB=390Ω, IO=15mA RB=750Ω, IO=10mA, VCC= 1.8V RB=390Ω, Vo=0.9V RB=390Ω, Vo=0.3V -MIN. 1.0 0.8 30 20 TYP. 1.2 1.0 0.1 0.1 -40 40 30 MAX. 0.2 0.2 -20 40 UNIT V V V V mA mA kΩ
Oscillator section PARAMETER Oscillation frequency Frequency change with voltage Frequency change with temperature SYMBOL f Δf / ΔV TEST CONDITIONS RT=3.0KΩ,CT=270pF VCC=2V to 15V Ta = 0℃to 85℃ MIN. 400 TYP. 500 2 MAX. 600 10 UNIT KHz %
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TYPICAL CHARACTERISTICS
Supply Voltage VS Supply Current
12 1.2
Supply Voltage VS Input Threshold Voltage
Ta=25℃
10
Input Threshold Voltage Vt (V)
8
Ta=25℃ RB=390Ω
VCC=2V 10
Supply Voltage (V) Figure 2
High Level Output High Level Output Voltage Vout (V)
1.2 1.0 0.8 0.6 0.4 0.2 0 VCC=2V RB=390Ω Ta=25℃
30
Input Threshold Voltage Variation △V/V(%)
Output Current Setting / Control section PARAMETER Pin voltage Output current setting resistance Input off condition Input on condition Pin current range SYMBOL VBR RB IOFF ION IBR TEST CONDITIONS RB=390Ω ---MIN. 0.15 300 -20 -1.8 TYP. 0.22 390 MAX. 0.3 5000 0 -45 -0.1 UNIT V Ω μA μA mA
1.0 0.8 0.6 0.4 0.2 0
Supply Current (mA)
8 6 4 2 0
0
4
12
16
20
0
4
ቤተ መጻሕፍቲ ባይዱ
8
12
16
20
Supply Voltage (V) Figure 1 Ambient Temperature VS Input Threshold Voltage Variation Ratio
1 2 3 4
8 7
SCP VCC BR/CTL OUT GND OSC COMP
2 3 4 5 6 7 8
CX8808
6 5
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DC ELECTRICAL CHARACTERISTICS(Ta=25℃,VCC=+2V, unless otherwise noted)
Under Voltage Lock-Out section (U.V.L.O.) PARAMETER Low threshold voltage Upper threshold voltage SYMBOL VLOW VUPPER TEST CONDITIONS --MIN. 1.1 TYP. 1.3 MAX. 0.9 1.5 UNIT V V
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DC ELECTRICAL CHARACTERISTICS (Cont.)
Error Amplifier section PARAMETER Input threshold voltage VT change with voltage VT change with temperature Input bias current Voltage Gain Frequency bandwidth Output voltage Swing Positive Negative SYMBOL VFB ΔVFB / ΔV ΔVFB / ΔT IB Av BW VPOS VNEG ISOURCE ISINK TEST CONDITIONS VCOMP=450mV VCC=2V to 15V Ta = -10℃to 85℃ --Av=0 dB --VCOMP=450mV MIN. 495 -1.0 0.78 24 TYP. 500 5 1 -0.2 100 6 0.87 0.05 -40 40 MAX. 505 20 1.0 0.2 -24 μA μA UNIT mV mV % μA V/V MHz V
FEATURES
˙Wide supply voltage operating range: 1.8 to 15V ˙Reference voltage precision: 2% ˙Low current consumption: Operation Mode 5.5mA Standby-by Mode 1μA ˙High speed oscillator frequency: 1MHz max. ˙Programmable Soft Start function (SS) ˙Short Circuit Protection function(SCP) ˙Totem-pole output with adjustable on/off current (for NPN transistors or n-channel MOSFET) ˙Logic level control stand-by mode function ˙Package: TS SOP8
Total device section PARAMETER Stand-by current Average supply current SYMBOL ISTANDBY IAVE TEST CONDITIONS Pin4 is open or VCC RB=390Ω,VCC=0~20V MIN. TYP. 5.0 MAX. 1 10 UNIT μA mA
Short Circuit Protection section (S.C.P.) PARAMETER Input source current S.C.P. threshold voltage SYMBOL ISCP VSCP TEST CONDITIONS VSCP= 0V -MIN. -1.5 0.7 TYP. -1.0 0.8 MAX. -0.7 0.9 UNIT μA V