bd9842fv ROHM Co. Ltd., bd9842fv Datasheet - Page 10

• Manufacturer Part Number: bd9842fv
• Description: Dual-output High Voltage High-frequency Step-down Switching Regulator Controller Type
• Manufacturer: ROHM Co. Ltd.

● Timing chart
1.8Vtyp.
0.9Vtyp.
Vcc-5V
◎Starting characteristics (UVLO cancel) and standby operation
◎Overcurrent detection (When output is shorted: Overcurrent detection and cancel are repeated at a specified time
VREF
VCC
STB
OUT
C5V
Vcc
SS
1V
interval.)
DT
FB
CT
Vcc-5V
VREF start voltage
VREF停止電圧
VREF stop voltage
canceled, (Vcc - 5V) Reg is started.
VREF起動電圧
UVLO(Vcc,VREF)とも解除になると
Vocpth
When UVLO (Vcc , and VREF) is
OCP+
OCP-
OUT
C5V
Vcc
Vcc
CT
DT
FB
SS
(Vcc-5V)Regが起動
(1) UVLO (Vcc) is canceled when Vcc>3.2V.
①Vcc＞3.2VでUVLO(Vcc)解除
UVLO protection
UVLO保護状態
condition
(2) UVLO (VREF) is canceled when VREF>2.2V.
②VREF＞2.2VでUVLO(VREF)解除
Overcurrent detection
UVLO (TSD) Minimum retention time (0.2 ms)
☆UVLO(TSD)最小保持時間(0.2msec)
(3) UVLO (C5V) is canceled when C5V<Vcc - 3V.
CT: Pull-up to VREF during UVLO period
CT
When 1. Vcc, 2. VREF, and 3. C5V are all in normal condition, UVLO is canceled after the minimum retention time.
When UVLO is detected at any of 1. Vcc, 2. VREF, and 3. C5V, output is stopped immediately.
③C5V＜Vcc-3VでUVLO(C5V)解除
■UVLOは、
①Vcc②VREF③C5V全てが通常状態となった後、☆最小保持時間後に解除、
①Vcc②VREF③C5VのいずれかでUVLOを検出した場合には、ただちに出力を停止。
OUT
UVLO
DT
:UVLO期間中はVREFにプルアップ
C5V
過電流検出
FB: Pull-down during UVLO
FB：UVLO期間中はプルダウン
FB
Delay time in detection
検出時の遅延時間
tdocpth
DT: Pull-down during UVLO
DT：UVLO期間中はプルダウン
Set SS by external capacity.
Although SS is notated by the same time axis in the figure for showing the image,
actually set sufficiently longer time in comparison with the cycle of triangular wave.
SSは外付け容量によって設定します。
図中ではイメージをつかんで頂く為同じ時間軸で表記しておりますが、
実際は三角波の周期に比べ十分に長い時間を設定します。
(FB→"L”)
DT→"L”
SS→"L”
10/15
Minimum time retaining detection condition
検出状態を保持する最小時間
Open DT (FB) and SS.
DT(FB)、SSを開放
tdocpre 1.6mS
OCP-
Overcurrent detection
過電流検出
tdocpre 1.6mS
OCP+
OUT
Overcurrent detection
過電流検出
C5V
Threshold voltage
(VCC)
Hysteresis
Threshold voltage
(VREF)
Threshold voltage
(C5V)
UVLO voltage [unit: V]
Item
Minimum
3.0
2.0
-
-
Standard
0.15
3.2
2.2
3.0
Maximum
0.25
3.4
2.4
3.4