BD9845FV Datasheet, PDF (10/16 Pages) Rohm – Single/Dual-output High-frequency Step-down Switching Regulator(Controller type)

BD9845FV
●Timing chart
◎Starting characteristics (UVLO cancel) and standby operation
VCC
(①1)VUcVc＞LO3.(2VVcでc)UiVsLcOa(nVccecl)e解d 除when Vcc>3.2V.
STB
1.8Vtyp. ^{VREF起動電圧}
0.9Vtyp. ^{VREF停止電圧}
VREF
Technical Note
(②2)VURVELFO＞(2V.2RVEでFU)VisLOca(VnRceElFe)d解w除hen VREF>2.2V.
SS
UVL_☆O_U(_VT_LS_OD_(T) _SM_Din_)最im_小um_保r_持et_時en_間tio₍n_0.2ti_mm_se_ec(0₎ .2 ms)
1V
SeStSSはS 外by付exけter容na量l cにapよacっityて. 設定します。
Al図tho中ugでh はSSイisメnーotジateをdつbyかthんe sでam頂eくt為im同e aじxi時s i間n t軸heでfig表ur記e fしorてshおowりinまgすthがe im、age,
ac実tua際llyはse三t s角uf波ficiのen周tly期lonにge比r tべim十e i分n cにom長paいri時son間wをith設th定e しcyまcleすo。f triangular wave.
■UVLOは、
①UVVLcOc②VREF③C5V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。
DT
UUVVLLO保O護状態
C_CT_T:_:P_UVul_Ll-_Ou_期p t_間o _中VR_はE_VF_Rd_Eu_Fr_にing_プU_ルV_アLO_ップperiod
FB
CT
D_DT_T:_：P_Uu_Vl_Ll-_Odo_期w_間n _中du_はrin_プg_ルU_ダVL_ウO_ン
OUT
C5V
When UVLO (Vcc , and VREF) is
ca^Un^Vc^Le^Ole^(Vd^c, ^c(V^,Vc^Rc^E-^F5^)とV^も) R^解e^除g ^にis ^なsta^るr^とted.
(Vcc-5V)Regが起動
Vcc
Vcc-5V
FFBB:：PUuVlLl-Odo期w間n 中duはrinプgルUダVLウOン
OUT
C5V
(3_③) U_CV_5VL_＜O _V(C_cc5_-V₃)_Vi_でs c_Ua_Vn_Lc_Oe₍le_Cd_5Vw_)解he_除n C5V<Vcc - 3V.
UVLO voltage [unit: V]
Item
Min
Threshold voltage (VCC)
3.0
Hysteresis
-
Threshold voltage (VREF)
2.0
Threshold voltage (C5V)
-
Typ Max
3.2 3.4
0.15 0.25
2.2 2.4
3.0 3.4
◎Overcurrent detection (When output is shorted: Overcurrent detection and cancel are repeated at a specified time interval.)
OCP+
OCP-
Vcc
Vocpth
DT
FB
CT
D_検e_出lay_時t_のim_ée _延in_時d_間etection
tdocpth
Overcurrent 過de電te流ct検ion出
FB
OCP-
OCP+
O過ve電rc流u検rre出nt detection O過v電er流cu検rre出nt detection
Mi検nim出u状m態tをim保e持reすtaるin最in小g 時de間tection condition
tdocpre 1^t.^d6^om^cpS^{re 1.6mS}
DT
SS
DT→"L”
SS→"L”
(FB→"L”)
ODpTe(nFBD)T、S(SFをB開) a放nd SS.
OUT
C5V
Vcc
Vcc-5V
OUT
C5V
www.rohm.com
© 2009 ROHM Co., Ltd. All rights reserved.
10/15
2009.05 - Rev.A